Question

Stacy recorded the number of minutes she used her

Answer 1

Using the t-distribution, the most appropriate conclusion for the hypotesis test is given by Phone use did not change.

How to find the value of z-statistic for population mean? (z test statistic)

Suppose we're specified that:

The sample mean = $\overline{x}$

The population mean =$\mu$

The population standard deviation = $\sigma$

The sample size = n

Then the z-statistic for this data is found as:

$Z = \dfrac{\overline{x} - \mu}{\sigma/\sqrt{n}}$

In this problem, the values of those parameters are as follows:

The sample mean  $\overline{x}$ =  -0.2

The population mean =$\mu$ = 0

The population standard deviation = $\sigma$ = 9.1

The sample size = n = 200

Hence, the test statistic is given by:

$Z = \dfrac{\overline{x} - \mu}{\sigma/\sqrt{n}}\\\\\\Z = \dfrac{-0.2- 0}{9.1/\sqrt{200}}\\\\z = 0.31$

Thus,

t = 0.31.

Since the absolute value of the test statistic is less than the critical value, we do not reject the null hypothesis and the conclusion is:

Phone use did not change.

Learn more about z-statistic here:

brainly.com/question/1640298

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