Suppose that medical expenses claimed by the taxpayers are normally distributed. A sample of 40 taxpayers claimed an average of $9,922 in medical expenses last year which produced a 95% confidence interval for the average medical expenses . Which of the following statements is a valid explanation for this confidence interval?

Refer to Exhibit 1. What is the standard deviation of the sampling distribution of the mean annual expenditures on food away from home for the sample of 16 households?

Refer to the Exhibit 3. What is the shape of the sampling distribution of the proportion?

Refer to Exhibit 1. Suppose that, using a sample of 50 patients, an 85% confidence interval for the average serial interval is constructed to be . Assuming that all else is constant, if the data from 100 patients is used, how will it affect the standard error of the mean and the resulting 85% confidence interval?

You will need to use Excel to answer the following questions.

Refer to Exhibit 2. What is the shape of the sampling distribution of the proportion of female gun owners in this example?

Suppose a regional CPA firm conducted an audit for a discount chain. One part of the audit involved developing a confidence interval for the mean dollar error in total charges that occur during the checkout. A simple random sample of 35 transactions was selected which showed that the average error in the sample was $0.88 with the standard deviation of $1.12. Find the margin of error for the 85% confidence interval for the mean dollar error in total charges.

In an examination of purchasing patterns of shoppers, a sample of 16 shoppers revealed that they spent, on average, $54 per hour of shopping with the standard deviation of $21 per hour of shopping. Assuming that the amount spent per hour of shopping is normally distributed in the population, find the margin of error for the 90% confidence interval for the mean amount. Please consult the critical values in the table below. Recall that the subscript refers to the area on the right of the critical value in the corresponding distribution. Critical Value df Value — 1.28 — 1.645 15 1.34 15 1.75

Refer to Exhibit 2. With the p-value equal to 0.016, what would be the conclusion at a 1% significance level?

Exhibit 2 A preference in humans for turning the head to the right, rather than to the left, during the first six months after birth constitutes one of the earliest examples of behavioral asymmetry and is thought to influence the subsequent development of perceptual preferences by increasing visual orientation to the right side. Suppose that you are trying to understand if this head-turning bias persists into adulthood by analyzing how adults turn their heads when kissing. If the head-turning bias does not persist, then half or 50% of adults should turn their heads to the right and 50% should turn their heads to the left when kissing. To test the head-turning bias in adulthood, you want to test if the proportion of adults who turn their heads to the left when kissing is below 50%. You observe kissing people in public places (international airports, large railway stations, beaches, and parks) recording the head-turning behavior of individuals. You find that, in the sample of 150 kissing adults you observed, 60 turned their heads to the left.