Answer:
The 85% confidence interval for the mean per capita income in thousands of dollars is between $20.4 and $21.8.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1-0.85}{2} = 0.075[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].
So it is z with a pvalue of [tex]1-0.075 = 0.925[/tex], so [tex]z = 1.44[/tex]
Now, find the margin of error M as such
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
[tex]M = 1.44\frac{12.6}{\sqrt{717}} = 0.7[/tex]
The lower end of the interval is the sample mean subtracted by M. So it is 21.1 - 0.7 = $20.4.
The upper end of the interval is the sample mean added to M. So it is 21.1 + 0.7 = $21.8.
The 85% confidence interval for the mean per capita income in thousands of dollars is between $20.4 and $21.8.
The equation having null set as its solution set is
A) x = cos x
B) x = e^x
C) x = sin x
D) x = tan x
Answer:
B) x = e^x
Step-by-step explanation:
The graphs of y = e^x and y = x never intersect, so the solution set will be the empty (null) set for ...
x = e^x
_____
There is one intersection of y=x with cos(x) and with sin(x). There are an infinite number of solutions for x = tan(x).
2/3 x G = 1/4
Solve for G!
(FIRST ANSWER GETS BRAINLIEST!)
Answer:
The value of G is 3/8 .
Step-by-step explanation:
In order to solve G, you have to divide 2/3 to both sides :
[tex] \frac{2}{3} \times G = \frac{1}{4} [/tex]
[tex] \frac{2}{3} \times G \div \frac{2}{3 } = \frac{1}{4} \div \frac{2}{3} [/tex]
[tex]G = \frac{1}{4} \times \frac{3}{2} [/tex]
[tex]G = \frac{3}{8} [/tex]
Answer:
3/8
Step-by-step explanation:
Convert to common denominator which would be 12.
8/12 x G=3/12
Then divide 3/12 by 8/12 and you get 3/8
Which statement best describes why the sale price is a function of the original price?
Answer:
see below
Step-by-step explanation:
A relation is a function when there is exactly one output for each input. That is the case in this table, so the relation between the original price and sale price is a function.
The formula for the surface area of a cylinder is SA= 2 pi r (h + r). What is the surface area of a cylinder when r = 3 centimetres and h = 4 centemeters?
The surface area of the cylinder, when the radius is 3 centimeters and the height is 4 centimeters, is approximately 131.88 square centimeters.
Use the provided formula for the surface area of a cylinder:
[tex]\[ SA = 2\pi r (h + r) \][/tex]
Given:
[tex]r = 3 \text{ centimeters}[/tex]
[tex]h = 4 \text{ centimeters}[/tex]
Now, substitute these values into the formula and calculate the surface area:
[tex]SA = 2\pi \times 3 \times (4 + 3)[/tex]
[tex]SA = 2\pi \times 3 \times 7[/tex]
[tex]SA = 6\pi \times 7[/tex]
[tex]SA = 42\pi[/tex]
Now, let's calculate the numerical value:
[tex]SA \approx 42 \times 3.14[/tex]
[tex]SA \approx 131.88 \text{ square centimeters}[/tex]
Therefore, the surface area of the cylinder, when the radius is 3 centimeters and the height is 4 centimeters, is approximately 131.88 square centimeters.
using the method of gauss to find the sum 2 + 4 + 6 + ... + 300
Answer:
22650
Step-by-step explanation:
Question 5
A restaurant bill is $80. Juan leaves a $20 tip. What percent tip is that?
Answer:
25%
Step-by-step explanation:
Plz mark me brainliest.
Answer:
25%
Step-by-step explanation:
In a large class of introductory Statistics students, the professor has each person toss a fair coin 1111 times and calculate the proportion of his or her tosses that were heads. The students then report their results, and the professor plots a histogram of these several proportions. a) What shape would you expect this histogram to be? Why? b) Where do you expect the histogram to be centered? c) How much variability would you expect among these proportions? d) Explain why a Normal model should not be used here.
Answer:
Given:
Sample size, n = 11
P = 0.5
a) The shape of the histogram will be symmetrical. This is because the probability of getting heads and tails is equal.
b) The histogram is centered at
p = 0.5 (because of equal probability of obtaining heads and tails).
c) How much variability would you expect among these proportions?
Here, we are to find the standard deviation.
Let's use the formula:
[tex] \sigma = \sqrt{\frac{pq}{n}} [/tex]
Where
p = 0.5(probability of getting heads)
q = 0.5 (probability of getting tails)
Therefore
[tex] \sigma = \sqrt{\frac{0.5 * 0.5}{11}} [/tex]
= 0.0227 ≈ 0.023
The standard deviation is 0.023
d) A normal model should not be use here because the success/failure condition is violated, since each student only flips the coin 11 times, it impossible to obtain both at least 10 heads and at least 10 tails. Here, the sample size is too small.
A study by the department of education of a certain state was trying to determine the mean SAT scores of the graduating high school seniors. The study examined the scores of a random sample of 81 graduating seniors and found the mean score to be 506 with a standard deviation of 83. At the 95% confidence level, find the margin of error for the mean, rounding to the nearest tenth. (Do not write \pm±).
Answer:
The margin of error for the mean is of 165.18 points.
Step-by-step explanation:
We have the standard deviation of the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 81 - 1 = 80
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 80 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 1.9901
The margin of error is:
M = T*s = 1.9901*83 = 165.18.
In which s is the standard deviation of the sample.
The margin of error for the mean is of 165.18 points.
Final answer:
The answer discusses z-scores for SAT scores, calculating scores above the mean, and comparing performance on different tests.
Explanation:
Z-score for SAT score of 720:
Calculate the z-score: z = (720 - 520) / 115 = 1.74.
Interpretation: A score of 720 is 1.74 standard deviations above the mean.
Math SAT score 1.5 standard deviations above the mean:
Calculate the score: 520 + 1.5(115) ≈ 692.5.
The score of 692.5 is 1.5 standard deviations above the mean of 520.
Better performance on math tests:
For SAT: z = (700 - 514) / 117 ≈ 1.59.
For ACT: z = (30 - 21) / 5.3 ≈ 1.70.
Person with a z-score closer to 2 performed better relative to the test they took.
Each group of students receives a bag that has 8 red cubes, 2 green cubes, and 10 blue cubes. If each group makes 100 pulls and replaces the cube after each pull, how many times would you expect them to draw a green cube?
Answer:
10 green cubes
Step-by-step explanation:
The total number of cubes is 8+2+10 = 20
The probability of drawing a green cube when there is replacement is
P(green) = green cubes/ total
=2/ 20
= 1/10
Multiply the probability by the number of draws to get the total number of cubes
1/10 * 100 draws = 10 green cubes
Expect 10 green cube draws in 100 pulls, with 8 red and 10 blue cubes also present.
To calculate the expected number of times a green cube is drawn, we can use the concept of probability.
In each pull, there are 20 cubes in total (8 red + 2 green + 10 blue). So, the probability of drawing a green cube in a single pull is:
[tex]\[ P(\text{green}) = \frac{\text{number of green cubes}}{\text{total number of cubes}} = \frac{2}{20} = \frac{1}{10} \][/tex]
Since each pull is independent and the cubes are replaced after each pull, the probability of drawing a green cube remains the same for each pull.
Therefore, the expected number of times a green cube is drawn in 100 pulls is:
[tex]\[ \text{Expected number of green draws} = P(\text{green}) \times \text{Total number of pulls} = \frac{1}{10} \times 100 = 10 \][/tex]
So, you would expect them to draw a green cube about 10 times in 100 pulls.
what are the first 5 terms of the sequence generated by the formula an= 2(n!)
Answer:
2, 4, 12, 48, 240
Step-by-step explanation:
We have the recursive formula a_n = 2*(n!)
Find:
a_1 = 2* 1! = 2
a_2 = 2*(2!) = 4
a_3 = 2*(3!) = 2*6 = 12
a_4 = 2*(4!) = 2*24 = 48
a_5 = 2*(5!) = 2*5*24 = 240
(1 point) Scores on a certain intelligence test for children between ages 13 and 15 years are approximately normally distributed with µ=106μ=106 and σ=24σ=24. (a) What proportion of children aged 13 to 15 years old have scores on this test above 92 ? Answer: Round to four decimal places. (b) What score which marks the lowest 25 percent of the distribution? Answer: Round to two decimal places. (c) Enter the score that marks the highest 5 percent of the distribution. Answer: Round to two decimal places.
Answer:
a) 0.719 = 71.90% of children aged 13 to 15 years old have scores on this test above 92
b) A score of 89.8 marks the lowest 25 percent of the distribution
c) A score of 145.48 marks the highest 5 percent of the distribution
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
[tex]\mu = 106, \sigma = 24[/tex]
(a) What proportion of children aged 13 to 15 years old have scores on this test above 92 ?
This is 1 subtracted by the pvalue of Z when X = 92. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{92 - 106}{24}[/tex]
[tex]Z = -0.58[/tex]
[tex]Z = -0.58[/tex] has a pvalue of 0.2810
1 - 0.2810 = 0.719
0.719 = 71.90% of children aged 13 to 15 years old have scores on this test above 92
(b) What score which marks the lowest 25 percent of the distribution?
The 25th percentile, which is X when Z has a pvalue of 0.25. So it is X when Z = -0.675.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]-0.675 = \frac{X - 106}{24}[/tex]
[tex]X - 106 = -0.675*24[/tex]
[tex]X = 89.8[/tex]
A score of 89.8 marks the lowest 25 percent of the distribution
(c) Enter the score that marks the highest 5 percent of the distribution
The 100-5 = 95th percentile, which is X when Z has a pvalue of 0.95. So it is X when Z = 1.645
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]1.645 = \frac{X - 106}{24}[/tex]
[tex]X - 106 = 1.645*24[/tex]
[tex]X = 145.48[/tex]
A score of 145.48 marks the highest 5 percent of the distribution
Final answer:
Using z-scores and the properties of a normal distribution, it was calculated that approximately 71.90% of children score above 92. The score marking the lowest 25 percent is approximately 90.20, and the score that marks the highest 5 percent of the distribution is around 145.88.
Explanation:
To solve the problems about normal distribution and interpreting IQ scores, we use the properties of the normal curve and z-scores. Z-scores help us understand how far away a particular score is from the mean, in terms of standard deviations.
Part (a): Proportion of Children With Scores Above 92
We first calculate the z-score for 92 using the formula: z = (X - μ) / σ, where X is the score, μ is the mean, and σ is the standard deviation. With μ = 106 and σ = 24, the z-score for 92 is (92 - 106) / 24 = -0.5833. Using a standard normal distribution table, we find that the proportion of children scoring above 92 corresponds to the area to the right of the z-score, which is approximately 0.7190. Therefore, the proportion of children aged 13 to 15 with scores above 92 is 0.7190.
Part (b): Lowest 25 Percent of the Distribution
The score marking the lowest 25 percent of the distribution corresponds to the 25th percentile or a z-score of about -0.675. We convert this z-score back to the original scale using the formula: X = μ + zσ, which yields X = 106 + (-0.675)(24) = 90.20. Thus, the score marking the lowest 25 percent is approximately 90.20.
Part (c): Highest 5 Percent of the Distribution
To find the score that marks the highest 5 percent, we locate the z-score that corresponds to the 95th percentile, which is about 1.645. Applying the conversion formula, we get X = 106 + (1.645)(24) = 145.88. Therefore, the score marking the highest 5 percent is approximately 145.88.
Rainwater was collected in water collectors at thirty different sites near an industrial basin and the amount of acidity (pH level) was measured. The mean and standard deviation of the values are 5.2 and 1.8 respectively. When the pH meter was recalibrated back at the laboratory, it was found to be in error. The error can be corrected by adding 0.2 pH units to all of the values and then multiply the result by 1.2. Find the mean and standard deviation of the corrected pH measurements.
Answer:
mean = 7.98; standard deviation = 2.52
Step-by-step explanation:
Kindly check the attached images below to see the step by step explanation to the question above.
The base of a cylinder has a radius of 9 centimeters. The cylinder is 12 centimeters tall. What is the approximate lateral area of the cylinder? Use 3.14 for π and round to the nearest whole number.
Answer:
The lateral area of the cylinder is 678cm²
Step-by-step explanation:
To calculate the lateral area of the cylinder we have to calculate the circumference and multiply it by the height
To solve this problem we need to use the circumferenc formula of a circle:
c = circumference
r = radius = 9cm
π = 3.14
c = 2π * r
we replace with the known values
c = 2 * 3.14 * 9cm
c = 56.52cm
The length of the circumference is 56.52cm
lateral area = c * h
56.52cm * 12cm = 678.24 cm²
round to the nearest whole number
678.24 cm² = 678cm²
The lateral area of the cylinder is 678cm²
Answer:
c-678 cm2
Step-by-step explanation:
what i got on edg 2020
Alice’s scores for five math test are: 85, 76, 81, 90, 88. What score must she achieve on the sixth test to give her an average of 85?
Mrs.Golden wants to cover her 6.5 by 4 bulletin board with silver paper that comes in 1-foot squares how many squares does Mrs.Golden need to cover her bulliten board will there be any pieces left over why or why not
Final answer:
Mrs. Golden will need 26 squares of silver paper to cover her bulletin board, and there will not be any pieces left over.
Explanation:
To find out how many 1-foot squares Mrs. Golden needs to cover her bulletin board, we first need to calculate the area of the bulletin board. The area of a rectangle can be found by multiplying the length and width. In this case, the length is 6.5 feet and the width is 4 feet, so the area is 6.5 feet x 4 feet = 26 square feet.
Since the silver paper comes in 1-foot squares, we can divide the area of the bulletin board by the area of each square to find out how many squares are needed. In this case, we divide 26 square feet by 1 square foot, giving us a result of 26 squares.
There will not be any pieces left over because 26 squares fully cover the area of the bulletin board. If there were any remaining space, we would need a fraction of a square to cover it.
What is the total surface area of the solid?
A rectangular prism with a length of 14 centimeters, width of 10 centimeters and height of 6 centimeters. A rectangular pyramid with 2 triangular sides with a base of 14 centimeters and height of 11 centimeters, and 2 triangular sides with a base of 10 centimeters and height of 12 centimeters.
558 square centimeters
702 square centimeters
842 square centimeters
982 square centimeters
Answer:
so the answer is b i did the quiz
Step-by-step explanation:
What is the total surface area of the solid?
A rectangular prism with a length of 14 centimeters, width of 10 centimeters and height of 6 centimeters. A rectangular pyramid with 2 triangular sides with a base of 14 centimeters and height of 11 centimeters, and 2 triangular sides with a base of 10 centimeters and height of 12 centimeters.
558 square centimeters
702 square centimeters
842 square centimeters
982 square centimeters
Answer:
B but i could be wrong
Step-by-step explanation:
n a survey of 700 year 2005 high school graduates, it was found that 50.3% had enrolled in colleges, 11.1% in vocational institutions, while the other 38.6% did not pursue any further studies. Perform a test of hypotheses to determine whether the college enrollment rate in the population of year 2005 high school graduates was significantly higher than 48%. (Calculate the P-value.) Round to four decimal places.
Answer:
[tex]z=\frac{0.503-0.48}{\sqrt{\frac{0.48(1-0.48)}{700}}}=1.218[/tex]
Now we can calculate the p value given by:
[tex]p_v =P(z>1.218)=0.1116[/tex]
Step-by-step explanation:
Information provided
n=700 represent the random sample selected
[tex]\hat p=0.503[/tex] estimated proportion of college enrollment
[tex]p_o=0.48[/tex] is the value that we want to test
z would represent the statistic
[tex]p_v[/tex] represent the p value (variable of interest)
System of hypothesis
we want to check if the true proportion for the college enrollment is higher thna 0.48, the system of hypothesis are:
Null hypothesis:[tex]p\leq 0.48[/tex]
Alternative hypothesis:[tex]p > 0.48[/tex]
The statistic is given by:
[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)
Replacing the info given we have:
[tex]z=\frac{0.503-0.48}{\sqrt{\frac{0.48(1-0.48)}{700}}}=1.218[/tex]
Now we can calculate the p value given by:
[tex]p_v =P(z>1.218)=0.1116[/tex]
8.73e16 in standerd form
Answer:
Hello,
Here is your answer:
The proper answer to this question is 87300000000000000.
Here is how:
8.73e16=87300000000000000.
Your answer is 87300000000000000.
If you need anymore help feel free to ask me!
Hope this helps!
(P.S. REMEMBER E IS EXPONET OR ^)
Which object has the mass of about one kilogram?
Answer:
A one-liter bottle of soda has a mass of about 1 kilogram.
Evaluate the following expression
40 -8 - 102
Answer:
-70
Step-by-step explanation:
40-8-102
= 32 - 102
= -70
To evaluate the expression 40 - 8 - 102, subtract 8 from 40 to get 32, then subtract 102 from 32 to arrive at -70.
40 - 8 - 102
To solve this expression, we need to follow the order of operations. In this case, since there are only subtraction operations involved, we can proceed from left to right.
40 - 8 = 32
32 - 102 = -70
This gives us the final answer: -70.
Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the correct position in the answer box. Release your mouse button when the item is place. If you change your mind, drag the item to the trashcan. Click the trashcan to clear all your answers.
Perform the following computation with radicals. Simplify the answer.
Answer:
[tex]\sqrt[4]{10x^2}[/tex]
Step-by-step explanation:
[tex]\sqrt[4]{5x}.\sqrt[4]{2x} = \sqrt[4]{5x * 2x} = \sqrt[4]{10x^2}[/tex]
Answer:
(10x²)^¼
Or,
10^¼ × x^½
Step-by-step explanation:
(5x)^¼ × (2x)^¼
[5x × 2x]^¼
(10x²)^¼
10^¼ × (x²)^¼
10^¼ × x^½
What is 99 divided by 6
Answer: 16.5
Step-by-step explanation:
[tex]\frac{99}{6} = 16.5[/tex]
Answer:
What i got is 16.5 hope this helps!
The two box plots show the data of the pitches thrown by two pitchers throughout the season. Which statement is correct? Check all that apply.
Answer:
Doesn’t show image
Step-by-step explanation:
Answer:
B,C
Step-by-step explanation
Pitcher 1 does not have a symmetric data set.
Pitcher 2 has a symmetric data set.
Find the unit vector in the direction of v=(7,-3).
(enter exact answers with square roots)
Answer:
[tex]\binom{ \frac{7 \sqrt{58} }{58} }{ \frac{ - 3 \sqrt{58} }{58} }[/tex]
Step-by-step explanation:
First, find the magnitude of the vector:
[tex] |v| = \sqrt{( {(7)}^{2} + {( - 3)}^{2}) } \\ = \sqrt{(49 + 9)} \\ = \sqrt{58} [/tex]
Then, divide each component of the vector by the magnitude to get the unit vector and rationalise:
[tex]unit \: vector = \binom{ \frac{7}{ \sqrt{58} } }{ \frac{ - 3}{ \sqrt{58} } } \\ = \binom{ \frac{7 \sqrt{58} }{58} }{ \frac{ - 3 \sqrt{58} }{58} } [/tex]
Of the 3737 people at a basketball team party, 2525 of them play basketball, 1515 are under six feet tall, and 5 do not play basketball and are six feet or taller. Determine the number of people at the party who play basketball and are under six feet tall, |B∩????||B∩U| , where BB represents the set of people at the party who play basketball and ????U represents the set of people at the party who are under six feet tall.
Answer:
8
Step-by-step explanation:
Universal Set, U=37
Number who play basketball, n(B)=25
Number who are under six feet, n(U)=15
Number of those who do not play basketball and are six feet or taller, n(B∪U)'=5
From set theory.
U=n(B)+n(U)-n(B∩U)+n(B∪U)'
37=25+15-n(B∩U)+5
37=45-n(B∩U)
Therefore:
n(B∩U)=45-37=8
Therefore, the number of people at the party who play basketball and are under six feet tall is 8.
The number of people at the party who play basketball and are under six feet tall is 1510. These people belong to both the group of basketball players and the group of people under six feet tall.
Explanation:To answer this question, we first need to understand who are the people at the party who play basketball and are under six feet tall. This group of people belongs to both the basketball players group represented by BB and the group of people under six feet tall, represented by U. We are looking for the intersection of these two groups, represented by |B∩U|.
Out of the 3737 people at the party, 2525 of them play basketball. From these 2525 basketball players, we don't know directly how many are under six feet tall. However, we are told that 1515 people at the party are under six feet tall. We also know that 5 people are over six feet tall and do not play basketball.
Therefore, to find out how many under six feet basketball players there are, we can subtract the 5 people who are over six feet and do not play basketball from the total of the ones who are under six feet: 1515 - 5 = 1510. So, there are 1510 people at the party who play basketball and are under six feet tall.
Learn more about Intersection of Sets here:https://brainly.com/question/33193647
#SPJ12
If A is 3 and C is 12, then 4AC equals...?
A. 19
B. 36
C.48
D.144
E. None correct
Answer:
144
Step-by-step explanation:
How many minutes have passed between the time shown on the first clock and the time shown on the second clock
If you add a pic maybe I could help but for now I cant
The hypotenuse of a right triangle is 10 feet long the longer leg is 2 feet longer than the shorter leg find the side side of the triangle
Answer:
square root of 96 or 9.79
Step-by-step explanation:
a2+b2=c2
2square+b2=10square
4+b2=100
(4-4)+b2=(100-4)
b2=square root96 or 9.79
My sister needs help
"Find the perimeter of the figure to the nearest hundredth."
Answer: 27.42 ft
Step-by-step explanation:
To find the perimeter first we must find the circumference of the circles.
You can easily find the diameter by subtracting and you get 6.
Using the circle circumference formula c=2piR you get 9.42.
9.42 is our circumference of one circle.
You don't need to divide this by 2 because you already have 2 halves of a circle.
Next add all the sides which is 18.
Add this to the circumference we calculated earlier which gives you 27.42 ft.
Weight of a rock: In a geology course, students are learning to use a balance scale to accurately weigh rocks. One student plans to weigh a rock 20 times and then calculate the average of the 20 measurements to estimate her rock's true weight. A second student plans to weigh a rock 5 times and calculate the average of the 5 measurements to estimate his rock's true weight. The student who weighs his rock 5 times uses the mean to calculate the 95% confidence interval for the rock weight (in grams). His interval is (25.2, 29.1). What does a 95% confidence interval for rock weight tell us in this case? Group of answer choices We are 95% confident that this interval includes the mean of the 5 weight measurements taken by this student. We are 95% confident that most rocks of this type weigh between 25.2 g and 29.1 g. We are 95% confident that the true weight of the rock is between 25.2 g and 29.1 g.
Answer:
We are 95% confident that the true weight of the rock is between 25.2 g and 29.1 g.
Step-by-step explanation:
Hello!
A geology student weighted a rock 5 times and estimated the average weight using a 95% CI [25.2; 29.1]gr
The confidence interval is used to estimate the value of the population mean, it gives you a range of values for it.
The 95% level of confidence of the interval indicates that if you were to construct 100 confidence intervals to estimate the population mean, you'd expect 95 of them to include the true value of the parameter.
So with a 95% confidence level, you'd expect the true average weight of the rock to be included in the interval [25.2; 29.1]gr
I hope this helps!