Question

1.      The heights are measured for supermodels Niki Taylor, Nadia Avermann, Claudia Schiffer, Elle Macpherson, Christy Turlington, Bridget Hall, Kate Moss, Valeria Mazza, Kristy Hume and seven other supermodels. They have a mean of 70.2 inches and a standard deviation of 1.5 inches. Use a 0.01 significance level to test the claim that supermodels have heights with a mean that is greater than the mean of 63.6 inches for women from the general population.

2.      A recent Gallup poll of 976 randomly selected adults showed that 312 of them never drank. Use the survey results to test the claim that less than 1/3 of all adults never drink. Use a =0.05.

3.      An economist wants to estimate the mean income for the first year of work for college graduates who had the profound wisdom of taking a statistics course. A random survey of 25 college graduates had a mean income of $56,700 for the first year of their work with standard deviation of $6,250. Find a 98% confidence interval for the true mean income.

4.      Nielsen Media Research wants to estimate the mean amount of time (in minutes) that full-time college students spend watching television each weekday. Find the sample size necessary to estimate that mean with a 15 minute margin of error. Assume that a 95% confidence level is desired. Also assume that a pilot study showed that the standard deviation is estimated to be 112.2 minutes.

5.      Find a 90% confidence interval estimate for the proportion of marriages that end in divorce in a certain urban area if in a survey of 360 marriages 126 ended in divorce.  

Answer 1

SOLUTION: