In: Statistics and Probability
7. The average payroll of all MLB teams in 2017 is estimated to be $155 million. A random sample of eight teams from the MLB this year was taken and the following payrolls were found, given in millions of dollars:
$199, $181, $173, $150, $122, $93, $81, $71
The mean and standard deviation of these eight teams is found to be $134 and $49 million, respectively.
(a) Obtain a 90% confidence interval for the mean payroll, in
millions of dollars, for all MLB teams.
(b) Interpret the results of the confidence interval found.
8. It is a common belief that the cost of living in Sacramento, CA is much higher than in most other cities around the country. The Income-to-Purchase Ratio (IPR), calculated by dividing average income by the average price of a home, is one way to compare cities, with a lower number representing a more expensive location to live. The IPR proportion of Miami, FL for civil engineers is 0.168; a random sample of 42 civil engineers in Sacramento, CA yielded an IPR proportion of 0.199. Use the following null and alternative hypotheses:
?0: ? = 0.168 and ??: ? > 0.168
(a) Perform a 1% significance level hypothesis test to determine
if the IPR proportion in Sacramento, CA is greater than the IPR
proportion of 0.168 in Miami, FL.
(b) Interpret the results of the hypothesis test performed.
7. a)
b) Interpretation :
For 100 samples drawn, sample mean will lie between (101.17, 166.83) for 90 samples.
8.
a) and b)