Homework Help for Statistics

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Question 9 of 14

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In a test of the effectiveness of garlic for lowering cholesterol, 49 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (before - after) in their levels of LDL cholesterol (in ma/dL) have a mean of 5.2 and a standard deviation of 16.5. Construct a 90% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL cholesterol?

Click here to view at distribution table.

Click here to view page 1 of the standard normal distribution table.

Click here to view page 2 of the standard normal distribution table.

What is the confidence interval estimate of the population mean u?

mg/dL <p< ma/dL

(Round to two decimal places as needed.)

What does the confidence interval suggest about the effectiveness of the treatment?

A.. The confidence interval limits contain 0, suggesting that the garlic treatment did affect the LDL cholesterol levels.

B. The confidence interval limits do not contain 0, suggesting that the garlic treatment did affect the LDL cholesterol levels.

O C. The confidence interval limits do not contain 0, suggesting that the garlic treatment did not affect the LDL cholesterol levels.

• D. The confidence interval limits contain 0, suggesting that the garlic treatment did not affect the LDL cholesterol levels.

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Question 8 of 14

This test: 14 points) possible

This question: 1 points) possible

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Refer to the accompanying data display that results from a sample of airport data speeds in Mbps. The results in the screen display are based on a 95% confidence level. Write a statement that correctly Interprets the confidence interval.

Tinterval

(13.046,22.15)

x= 17.598

Sx= 16.01712719

n = 50

Choose the correct answer below.

O A. We have 95% confidence that the limits of 13.05 Mbps and 22.15 Mbps contain the true value of the mean of the population of all data speeds at the airports

O B. The limits of 13.05 Mbps and 22.15 Mbps contain 95% of all of the data speeds at the airports.

O C. We have 95% confidence that the limits of 13.05 Mbps and 22.15 Mbps contain the sample mean of the data speeds at the airports.

O D. The limits of 13.05 Mbps and 22.15 Mbps contain the true value of the mean of the population of all data speeds at the airports.

Answer number 6 in this picture

Here are summary statistics for randomly selected weights of newborn girls: n = 36, x = 3222.2 g, s = 686.7 g. Use a confidence level of 99% to complete parts (a)

through (d) below.

a. Identify the critical value ta/2 used for finding the margin of error.

4/2=0

(Round to two decimal places as needed.)

b. Find the margin of error.

E= 0 g

(Round to one decimal place as needed.)

c. Find the confidence interval estimate of p.

(Round to one decimal place as needed.)

d. Write a brief statement that interprets the confidence interval. Choose the correct answer below.

A data set Includes 109 body temperatures of healthy sdult humans having a mean of 98.2°F and a standard deviation of 0.62°F. Construct a 99% confidence interval estimate of the mean body temperature of all healthy humans. What does the sample suggest about the use of 98.6°F as the mean body temperature?

Click here to view a t distribution table.

Click here to view page 1 of the standard normal distribution table, Click here to view page 2 of the standard normal distribution tabile

What is the confidence interval estimate of the population mean p?

7°F

(Round to three decimal places as needed.)

What does this suggest about the use of 98.6°F as the mean body temperature?

O A. This suggests that the mean body tamperaturd could very possibly be 98.6°F.

• B. This suggests that the mean body temperature is lower than 98.6°F.

O c. This suggests that the mean body temperature is higher than 98.6°F.

Some states now allow online gambling. As a marketing manager for a casino, you nised to determine the percentage of adults in those states who gamble online. How many adults must you survey in order to be 95% corfident that your estimate is in error by no more than one percentage point? Complete parts (a) and (b) below.

a. Assume that nothing is known about the paroanitage of adults who gamble ori neR

(Round up to the nearest integer.)

b. Assume that 18% of all adults gamble online.

naB

(Round up to the nearest integer.)

In a science fair project, Emily conducted an experiment in which she tested professional touch therapists to see if they could sense her energy field. She flipped a coin to select either her right hand or her left hand, and then she asked the therapists to identify the selected hand by placing their hand just under Emily's hand without seeing it and without touching it. Among 326 trials, the touch therapists were correct 152 times. Complete parts (a) through (d).

Question 15 of 16

Assure that a randomly selected subject is given a bone density test. Those test scores are normally distributed with a mean of 0 and a standard deviation of 1. Find the probability that a given score Is between - 2.07 and 3.66 and draw a sketch of the region.

Sketch the region, Choose the correct graph below

The probability is ____.

(Round to four decimal places as needed.)

Question 14 of 16

Assume that a randomly selected subject is given a bons density test. Those test scores are normally distributed with a mean of 0 and a standard deviation of 1. Find the probability that a given score is less than - 0.78 and draw a sketch of the region.

Sketch the region. Choose the correct graph below

The probability is ____.

(Round to four decimal places as needed.)

Find the areas of the shaded region. The graph to the right depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15.

The area of the shaded region is _____.

(Round to four decimal places as needed.)

Assume that females have pulse rates that are normally distributed with a mean of = 72.0 beats per minute and a standard deviation of = 12.5 beats per minute.

Complete parts (a) through (c) below.

a. If 1 adult female Is randomly selected, find the probability that her pulse rate is less than 78 beats per minute.

The probability is ____.

(Round to four decimal places as needed.)

b. If 16 adult females are randomly selected. find the probability that they have pulse rates with a mean less than 78 beats per minute.

The probability is ____.

(Round to four decimal places as needed.)

c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30?

◯ A. Since the mean pulse rate exceeds 30, the distribution of sample means is a normal distribution for any sample size.

◯ B. Since the original population has a normal distribution, , the distribution of sample means is a normal distribution for any sample size.

◯ C. Since the distribution is of sample means, not individuals, the distribution is a normal distribution for any sample size.

◯ D. Since the distribution is of individuals, not sample means, the distribution is a normal distribution for any sample size.

The overhead reach distances of adult females are normally distributed with a mean of 205.5 cm and a standard deviation of 8.3 cm.

a. Find the probability that an individual distance is greater than 214.80 cm.

b. Find the probability that the mean for 20 randomly selected distances is greater than 203.70 cm.

c. Why can the normal distribution be used in part b, even though the sample size does not exceed 30?

a. The probability is ____.

(Round to four decimal places s needed.)

b. The probability is ____.

(Round to four decimal places as needed.)

c. Choose the correct answer below.

◯ A. The normal distribution can be used because the original population has a normal distribution.

◯ B. The normal distribution can be used because the finite population correction factor is small.

◯ C. The normal distribution can be used because the mean is large

◯ D. The normal distribution can be used because the probability is less than 0.5

Engineers want to design seats in commercial aircraft so that they are wide enough to fit 99% of all adults. (Accommodating 100% of adults would require very wide seats that would be much too expensive.) Assume adults have hip widths that are normally distributed with a men of 142 In. and a standard deviation of 0.9 in. Find P99. That Is, find the hip with for adults that separates the smallest 99% from the largest 1%

What is the maximum hip width that is required to satisfy the requirement of fitting 99% of adults?

____ in. (Round one decimal place as needed)

Find the area of the shaded region. The graph to the right depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15.

The area of the shaded region is _____. (Round to four decimal places as needed.)

Assume that adults have IQ scores that are normally distributed with a mean of 103.7 and a standard deviation of 19 find the first quartile which is the IQ score separating the bottom 25% from the top 75%. (Hint: Draw a graph.)

The first quartile is ______

 (Type an integer or decimal rounded to one decimal place as needed.)