Question

2. The following figures include a sample of the MPG of small SUV's 25 24 22 22 23 25 24 Construct a 95% confidence interval estimate for the population mean MPG of small SUV's, assuming a normal distribution. (check figure: upper end of the population mean estimate is $23.61)

Answer 1

Answer:

n= 20, c= 95%

now calculate the sample mean and sample standard deviation

for given data we get,

$\bar x$= 22.85, s= 1.631111988

formula for confidence interval is

Itc*

Where tc is the t critical value for c= 95% and df =n-1 =20-1 =19

tc =2.093

1.631112 22.85 + 2.093 * V20

22.85 − 0.763 < $\mu$ < 22.85 + 0.763

( 22.087 , 23.613 )

Thus we get confidence interval = ( 22.087 , 23.61 )

Lower bound = 22.087

Upper bound = 23.613