Answer:
Test statistic = 3.1587
Step-by-step explanation:
We are given that the Toy-lot company makes an electric train with a motor that it claims will draw an average of only 0.8 ampere (A).
Also, a sample of eleven motors was tested, and it was found that the mean current was x = 1.20 A, with a sample standard deviation of s = 0.42 A.
So, Null Hypothesis, :
= 0.8 { claim of 0.8 A is not low}
Alternate Hypothesis, :
> 0.8 { claim of 0.8 A is too low}
Now, the test statistics used here will be;
T.S. = ~
where, X bar = sample mean = 1.20 A
s = sample standard deviation = 0.42 A
n = sample size = 11 motors
So, Test statistics = ~
= 3.1587
At 1% level of significance, t table gives a critical value of 2.764 at 10 degree of freedom. Since our test statistics is higher than the critical value so we have sufficient evidence to reject null hypothesis .
Therefore, we conclude that Toy-lot claim of 0.8 A is too low.