please choose one of the answers in the choices
QUESTION 1
Private colleges and universities rely on money contributed by individuals and corporations for their operating expenses. Much of this money is put into a fund called an endowment, and the college spends only the interest earned by the fund.A recent survey of 8 private colleges in the United States revealed the following endowments (in millions of dollars):60.2,47.0,235.1,490.0,122.6,177.5,95.4,and 220.0.Summary statistics yield sample mean 180.975 with standard deviation 143.042.Calculate a 95% confidence interval for the mean endowment of all the private colleges in the United States assuming a normal distribution for the endowments.
$180.975+$94.066
$180.975$99.123
$180.975$116.621
$180.975$119.586
QUESTION 2
A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of 72 statistics students generated the following 90% confidence interval:(0.438,0.642.Based on the interval above,is the population proportion of females equal to 0.60 No,and we are 90% sure of it.
No.The proportion is 54.17%
Maybe.0.60 is a believable value of the population proportion based on the information above
Yes,and we are 90% sure of it.
QUESTION 3
50 individuals resulted in an average income of $15,000.What is the width of the 90% confidence interval? $232.60 $364.30 $465.23 $728.60
QUESTION 4
A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chaina s new store in the mall Fifteen credit card accounts were randomly sampled and analyzed with the following results:the sample mean $50.5 and variance $400.Construct a 95% confidence interval for the average amount its credit card customers spent on their first visit to the chain's new store in the mall assuming that the amount spent follows a normal distribution.
$50.50+$9.09
$50.5010.12
$50.50$11.00
$50.50$11.08