Question

1. A food safety guideline is that the mercury in fish should be below 1 part per million (ppm). Listed below are the amounts of mercury (ppm) found in tuna sushi sampled at different stores in a major city. Find the margin error for 95% confidence interval and construct a 95% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna sushi? Mecury(ppm) .50 .079 .0.09 .89 1.29 .59 .91.

2. An IQ test is designed so that the mean is 100 and the standard deviation is 23 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 90% confidence that the sample mean is within 6 IQ points of the true mean. Assume that =23 and determine the required sample size using technology.

Answer 1

Date: 11/06/2019 Answer The margin oferror for 95% confidence interval is, By using Excel, find margin of error with the help of following steps is: 1) 2) 3) 4) 5) 6) Import the data Select the MegaStat from Add-Ins Menu Select Mean vs. Hypothesized Value from Hypothesis Tests. Enter Summary Input and Hypothesized mean. Select t-test, Alternative and Confidence Level Click Ok Hypothesis Test: Mean vs. Hypothesized Value 0.621286 mean Mercury 0.446238 std. dev 0.168662 std. error 7 n 6 df 0.208585 confidence interval 95.% lower 1.033987 confidence interval 95.% upper 0.412701 margin of error

From the Excel output, the margin of error for 95% confidence interval is 0.41 A 95% confidence interval estimate of the mean amount of mercury in the population is, From Excel output, a 95% confidence interval estimate of the mean amount of mercury in the populationis |0.21 to 1.03 It does not appear that there is too much mercury in tuna sushi due to a 95% confidence interval estimate of the mean amount of mercury in the population is between 0.21 and 1.03 does include 1.00 The sample size is, By using Excel software, find sample size with the help of following steps: 1) 2) 3) 4) 5) Import the data Select Sample size from MegaStat option in Add-Ins menu Enter E and Std dev. Select Confiden ce Level. wwwww. Click Ok.

Sample size -mean 6 E, error tolerance 23 standard deviation 90% confidence level 1.645 z 39.756 sample size 40 rounded up From the Excel output, the sample size is 40