# The results of a study of 268 students who paid a private tutor to help them improve their scores on a standardized test are shown below. The changes in both the7Mathematics and Verbal scores for these students are reproduced in the table. Complete parts a through c belowTest score improvementsMean change in scoreStandard deviation of score changesMathVerbal176749tsho pomor we above nervalbraryb. Construct and interpret a 95% confidence interval for the population mean change in the Verbal score for students who pay a private tutorfrect: 0ions(Round to three decimal places as needed.)Enter your answer in the edit fields and then click Check Answer>Check AnswerClear Allpartsremaining1256 AM10/30/2019aype here to search

Question

Part b. Please show TI 84 steps help_outlineImage TranscriptioncloseThe results of a study of 268 students who paid a private tutor to help them improve their scores on a standardized test are shown below. The changes in both the 7 Mathematics and Verbal scores for these students are reproduced in the table. Complete parts a through c below Test score improvements Mean change in score Standard deviation of score changes Math Verbal 17 67 49 ts ho po mor we above nerval brary b. Construct and interpret a 95% confidence interval for the population mean change in the Verbal score for students who pay a private tutor frect: 0 ions (Round to three decimal places as needed.) Enter your answer in the edit fields and then click Check Answer > Check Answer Clear All parts remaining 1256 AM 10/30/2019 a ype here to search fullscreen
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Step 1

Confidence interval when population standard deviation is not known:

The formula of confidence interval for the population mean when population standard deviation is not given is as follows.

Step 2

Computing the 95% confidence interval for population mean:

Here, the sample mean (x-bar) is 9.

The sample standard deviation (s) is 49.

The confidence level is 0.95.

Thus, the level of significance, α is 0.05 (= 1 – 0.95).

The degrees of freedom (n − 1) is 267 (=268 − 1).

Step 3

T1-84 procedure to obtain 95% confidence interval:

• Press the STAT button and highlight TESTS.
• Scroll down to 8: TInterval
• Highlight Stats and hit ENTER
• Choose STATS, Enter values for S as 49, x-bar as 9, n as 268, a...

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