Question

A scrap metal dealer claims that the mean of his cash scales is "no more than $80," but an Internal Revenue Service agent believes the dealer is truthful. Observing a sample of 20 cash customers, the agent finds the mean purchases to be $91, with a standard deviation of $21. Assuming the population is approximately normally distributed, and using the 0.05 level of significance, what is the calculated value of test statistic

Answer 1

Answer: 2.3425

Explanation:

As per given , we have

`\mu=80`

n = 20

`\overline{x}=91\\\\ s=21`

We assume that the population is approximately normally distributed.

Since population standard deviation is unknown , so we use t-test.

Test statistic :
`t=\frac{\overline{x}-\mu}{(\sigma)/(√(n))}`

`\\\\ t=(91-80)/((21)/(√(20)))=2.342547405\approx2.3425`

Hence, the calculated value of test statistic = 2.3425