Question

Suppose that a software development team released an update to one of their mobile applications after receiving complaints about the previous version from 9.4% of their customers. A few weeks after the update was released, the development team wanted to know if fewer customers had complaints. The team selected a random sample of 325 customers and found that 21 of them submitted complaints about the application after the update was released.

The team wants to use a one‑sample  z ‑test for a population proportion to see if the proportion of customers with complaints,  p, has decreased since they released the update. For this test, they plan to use a significance level of  α=0.05 .

Determine the value of the z ‑test statistic. Give your answer precise to at least three decimal places

z =

Determine the critical value, Zα , for this test. Give your answer precise to at least three decimal places

Za =

Answer 1

Solution:

Conclusion: Hence there is strong evidence to support that the proportion of customers with complaints,

p, has decreased since they released the update.

Done