The test statistic of zequalsnegative 2.01 is obtained when testing the claim that pless than0.18. a. using a significance level of alphaequals0.05, find the critical value(s). b. should we reject upper h 0 or should we fail to reject upper h 0?

(a) The critical value is -1.64.

(b) We fail to reject the null hypothesis H₀.

Step-by-step explanation:

(a)

The test statistic of z=-2.01 is obtained when testing the claim that p<0.18. It means the data belongs to normal distribution.

Null hypothesis:

Alternative hypothesis:

It is left tailed test.

Using a significance level of α=0.05 we need to find the critical value.

From the standard normal table the critical value at α=0.05 for left tailed is -1.64.

Therefore the critical value is -1.64.

(b)

If z > critical value, then we reject the null hypothesis.

If z < critical value, then we fail to reject the null hypothesis.

In the given problem z=-2.01 and critical value = -1.64.

Since z < critical value, therefore we fail to reject the null hypothesis H₀.

answer: the common difference is -0.10

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads