(c) without assuming anything about the distribution of times, what can be said about the percentage of times that are either less than 19 minutes or greater than 55 minutes? (Round the answer to the nearest whole number.)

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We showed that 19 minutes and 55 minutes (are/are) not 3 standard deviations from the mean.

When we assume nothing about the shape of the distribution, we will use Chebyshev's Rule to get a sense of the distribution of data values. Chebyshev's Rule will tell us
the minimum percentage of observations that are within k standard deviations of the mean when k 2 1.
100 1 -
%
We previously determined that 25 is two standard deviations below the mean and 49 is two standard deviations above the mean. Thus, we will use k =
2 in
Chebyshev's Rule to determine the minimum percentage of times that are between 25 and 49 minutes.
100 1- - 1% = 100 1-
75
75 %
Thus, at least 75
75 % of times are between 25 and 49 minutes.
Step 4
(c) Without assuming anything about the distribution of times, what can be said about the percentage of times that are either less than 19 minutes or greater than
55 minutes? (Round the answer to the nearest whole number.)
Again, we are not assuming anything about the shape of the distribution, so we will continue using Chebyshev's Rule. We will determine the minimum percentage of
times that are between 19 minutes and 55 minutes and then determine the maximum percentage of times that are less than 19 minutes or greater than 55 minutes.
First, we need to know how many standard deviations 19 minutes and 55 minutes are from the mean so we can determine the value for k.
We previously determined that 43 minutes and 31 minutes are 1 standard deviation from the mean and that 49 minutes and 25 minutes are 2 standard deviations from
the mean.
25
31
37
43
49
X-3s
X-25
X-5
X+5
X+ 25
X+35
Perhaps 19 minutes and 55 minutes are 3 standard deviations from the mean. Let's investigate.
3 standard deviations above the mean
x + 3s = 37 +:
3 standard deviations below the mean
3s - 37 - 3
We showed that 19 minutes and 55 minutes-Select-- v3 standard deviations from the mean.
Transcribed Image Text:When we assume nothing about the shape of the distribution, we will use Chebyshev's Rule to get a sense of the distribution of data values. Chebyshev's Rule will tell us the minimum percentage of observations that are within k standard deviations of the mean when k 2 1. 100 1 - % We previously determined that 25 is two standard deviations below the mean and 49 is two standard deviations above the mean. Thus, we will use k = 2 in Chebyshev's Rule to determine the minimum percentage of times that are between 25 and 49 minutes. 100 1- - 1% = 100 1- 75 75 % Thus, at least 75 75 % of times are between 25 and 49 minutes. Step 4 (c) Without assuming anything about the distribution of times, what can be said about the percentage of times that are either less than 19 minutes or greater than 55 minutes? (Round the answer to the nearest whole number.) Again, we are not assuming anything about the shape of the distribution, so we will continue using Chebyshev's Rule. We will determine the minimum percentage of times that are between 19 minutes and 55 minutes and then determine the maximum percentage of times that are less than 19 minutes or greater than 55 minutes. First, we need to know how many standard deviations 19 minutes and 55 minutes are from the mean so we can determine the value for k. We previously determined that 43 minutes and 31 minutes are 1 standard deviation from the mean and that 49 minutes and 25 minutes are 2 standard deviations from the mean. 25 31 37 43 49 X-3s X-25 X-5 X+5 X+ 25 X+35 Perhaps 19 minutes and 55 minutes are 3 standard deviations from the mean. Let's investigate. 3 standard deviations above the mean x + 3s = 37 +: 3 standard deviations below the mean 3s - 37 - 3 We showed that 19 minutes and 55 minutes-Select-- v3 standard deviations from the mean.
Step 1
(a) What value is 1 standard deviation above the mean? 1 standard deviation below the mean? What values are 2 standard deviations away from the mean?
To find the value that is some number of standard deviations above or below the mean, we will add or subtract some multiple of the standard deviation, s, to the sample
mean, x. The average playing time was given to be 37 minutes with a standard deviation of 6 minutes, so we have x = 37
37 and s = 6
To find a value above the mean indicates we will use addition
addition . Finding a value below the mean indicates we will use
subtraction
subtraction. Finding values that are away from the mean includes values that are above and below the mean, indicating we will use
addition and subtraction
addition and subtraction
Step 2
We know the mean is x = 37 and the standard deviation is s = 6. To find values above the mean indicates addition, values below the mean indicates subtraction, and both
addition and subtraction will be used to find values away from the mean.
Find the value that is 1 standard deviation above the mean.
1 standard deviation above the mean = x+s
= 37 + 6
43
43
Find the value that is 1 standard deviation below the mean.
1 standard deviation below the mean = x -s
= 37 - 6
31
Find the values that are 2 standard deviations away from the mean.
2 standard deviations above the mean = x + 25
= 37 + 2 6
6)
49
49
2 standard deviations below mean = x - 25
= 37 - 26
25
25
Transcribed Image Text:Step 1 (a) What value is 1 standard deviation above the mean? 1 standard deviation below the mean? What values are 2 standard deviations away from the mean? To find the value that is some number of standard deviations above or below the mean, we will add or subtract some multiple of the standard deviation, s, to the sample mean, x. The average playing time was given to be 37 minutes with a standard deviation of 6 minutes, so we have x = 37 37 and s = 6 To find a value above the mean indicates we will use addition addition . Finding a value below the mean indicates we will use subtraction subtraction. Finding values that are away from the mean includes values that are above and below the mean, indicating we will use addition and subtraction addition and subtraction Step 2 We know the mean is x = 37 and the standard deviation is s = 6. To find values above the mean indicates addition, values below the mean indicates subtraction, and both addition and subtraction will be used to find values away from the mean. Find the value that is 1 standard deviation above the mean. 1 standard deviation above the mean = x+s = 37 + 6 43 43 Find the value that is 1 standard deviation below the mean. 1 standard deviation below the mean = x -s = 37 - 6 31 Find the values that are 2 standard deviations away from the mean. 2 standard deviations above the mean = x + 25 = 37 + 2 6 6) 49 49 2 standard deviations below mean = x - 25 = 37 - 26 25 25
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