Yahoo Answers: Answers and Comments for Math Homework Help? [Mathematics]
Copyright © Yahoo! Inc. All rights reserved.
https://answers.yahoo.com/question/index?qid=20190620172215AA92XI4
From Anonymous
enUS
Thu, 20 Jun 2019 17:22:15 +0000
3
Yahoo Answers: Answers and Comments for Math Homework Help? [Mathematics]
292
38
https://answers.yahoo.com/question/index?qid=20190620172215AA92XI4
https://s.yimg.com/zz/combo?images/emaillogous.png

From Puzzling: The first step is converting each raw score in...
https://answers.yahoo.com/question/index?qid=20190620172215AA92XI4
https://answers.yahoo.com/question/index?qid=20190620172215AA92XI4
Thu, 20 Jun 2019 19:22:01 +0000
The first step is converting each raw score into a zscore. The zscore represents how many standard deviations the raw score is away from the mean.
PART A:
10 minutes is 0.3 minutes above the mean.
10  9.7 = 0.3
Divide by the standard deviation to find that we are about 1/7 of a standard deviation above the mean.
z = 0.3 / 2.1
z = 1/7
z ≈ 0.143
Use your calculator or your table to figure out P(z < 0.143)
PART B:
5 minutes is below the mean:
5  9.7 = 4.7
Divide by the standard deviation to get the zscore.
z = 4.7 / 2.1
z ≈ 2.238
Use your calculator or your table to figure out P(z > 2.238)
PART C:
The raw scores are 8 and 15.
8 minutes:
z1 = (8  9.7) / 2.1
z1 = 1.7 / 2.1
z1 ≈ 0.81
15 minutes:
z2 = (15  9.7) = 5.3
z2 = 5.3 / 2.1
z2 ≈ 2.52
You want to calculate P(0.81 < z < 2.52)
If you want to doublecheck your answers, use the following online calculator.