4. Assume that we want to construct a confidence interval. Do one of thefollowing, asappropriate: (a) find the critical value t/2, (b) find the critical value z/2,or(c) state that neither the normal distribution nor the t distribution applies. Here are summary statistics for randomly selected weights of newborngirls: n=208,x=29.9 hg, s=7.6 hg. The confidence level is 95%.

6.) In a test of the effectiveness of garlic for loweringcholesterol, 48 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (beforeafter) in their levels of LDL cholesterol(in mg/dL) have a mean of 3.1 and a standard deviation of 18.4. 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 LDLcholesterol?

7.) 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. Construct a 99% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tunasushi?

0.51 0.77 0.10 0.87 1.24 0.54 0.89

8.) Listed below are the amounts of net worth(in millions ofdollars) of the ten wealthiest celebrities in a country. Construct a 90% confidence interval. What does the result tell us about the population of allcelebrities? Do the data appear to be from a normally distributed population asrequired?

244 190186166163 162 163 162154154154 149

9.) The pulse rates of 153randomly selected adult males vary from a low of 36 bpm to a high of 96 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 98% confidence that the sample mean is within 3 bpm of the population mean. Complete parts(a) through(c) below.