Question

The Toylot company makes an electric train with a motor that it claims will draw an average of only 0.8 ampere (A) under a normal load. A sample of nine motors was tested, and it was found that the mean current was x = 1.34 A, with a sample standard deviation of s = 0.48 A. Do the data indicate that the Toylot claim of 0.8 A is too low?

What is the value of the sample test statistic? (Round your answer to three decimal places.)Find the P-value. (Round your answer to four decimal places.)

Answer 1

Explanation:

Given that population average is 0.8 ampere

Sample size = 9

Sample mean x bar = 1.34 A

Sample std dev s = 0.48

`H_o: x bar =0.8\\H_a: x bar >0.8`

(one tailed test)

Mean difference -
`1.34-0.8 =0.54`

Std error =
`(s)/(√(n) ) =0.16`

t test can be used since sigma is not known and sample size small

t statistic = mean diff/std error = 3.5

df = 8

p value = 0.00404