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Chapter 10: Q. 67 (page 599)

Use the following information to answer the next five exercises. A study was conducted to test the effectiveness of a software patch in reducing system failures over a six-month period. Results for randomly selected installations are shown in Table 10.21. The 鈥渂efore鈥� value is matched to an 鈥渁fter鈥� value, and the differences are calculated. The differences have a normal distribution. Test at the 1% significance level.

What conclusion can you draw about the software patch?

Short Answer

Expert verified

Reject the null hypothesis with p - value of 0.0067.

There is enough data to show that installing a software patch lowers system failures.

Step by step solution

01

Given information

The table is

02

Step 2: 

Test at 1%level of significance, that is,伪=0.01

The output from Exercise 10.49 is :

As伪>p-value, need not reject the null hypothesis.

At 1%level of significance, there is sufficient evidence to back up the assertion that the software patch reduces the number of system failures.

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