Question

In a crash test of 26 minivans of a Japanese manufacturer, collision repair costs are found to have a distribution that is roughly bell shaped, with a mean of $1850 and a standard deviation of $340. Construct a 95% confidence interval for the mean repair cost in all such vehicle collisions by filling in the following blanks

df =

Critical value = Point Estimate =

Standard Error of the Estimate =

Margin of Error =

Lower Confidence Limit =

Upper Confidence Limit =

Answer 1

n= 26

s = 340

d.f= n - 1 = 26 - 1 = 25

Critical value = 2.060

Point Estimate = 1850

standard error = se

95% confidence interval

Formula

E = Margin of Error

tc = 2.060 ( using t-table )

Margin of Error = 137.3603

95 % confidence interval is

Lower Confidence Limit = 1712.6397

Upper Confidence Limit = 1987.3603