SOLUTION: I am having trouble finding the answer to E and F in this problem. could you show me how to do letter E using the formula and also letter F.
The following are scores on a test i
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-> SOLUTION: I am having trouble finding the answer to E and F in this problem. could you show me how to do letter E using the formula and also letter F.
The following are scores on a test i
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Question 852643: I am having trouble finding the answer to E and F in this problem. could you show me how to do letter E using the formula and also letter F.
The following are scores on a test in a math class.
67 89 94 55 76 71 66 87 69 74 99
84 55 42 68 77 90 88 81 78 65 79
98 64 77 70 85 89 92 72 61 94 83
a. Find the mean.
I have the mean as 2539/33= 76.9393
would you round this to the whole number?
b. Find the median.
I have the median as 77
c. Find the mode.
i have the mode as 55,77,89
d. Find the range.
I have the range as 57
e. Find the standard deviation.
f. How many of the scores are within one standard deviation of the mean?
Hi,
My point in doing the following is to encourage You to use a spreadsheet or Calculator
The IMPORTANT thing is to relatively easily find the standard deviation,
so as to not forget the purpose of doing so in the process.
m (x-µ) (x-µ)^2
42 76.94 -34.94 1220.804
55 76.94 -21.94 481.364
55 76.94 -21.94 481.364
61 76.94 -15.94 254.084
64 76.94 -12.94 167.444
65 76.94 -11.94 142.564
66 76.94 -10.94 119.684
67 76.94 -9.94 98.804
68 76.94 -8.94 79.924
69 76.94 -7.94 63.044
70 76.94 -6.94 48.164
71 76.94 -5.94 35.284
72 76.94 -4.94 24.404
74 76.94 -2.94 8.644
76 76.94 -0.94 0.884
77 76.94 0.06 0.004
77 76.94 0.06 0.004
78 76.94 1.06 1.124
79 76.94 2.06 4.244
81 76.94 4.06 16.484
83 76.94 6.06 36.724
84 76.94 7.06 49.844
85 76.94 8.06 64.964
87 76.94 10.06 101.204
88 76.94 11.06 122.324
89 76.94 12.06 145.444
89 76.94 12.06 145.444
90 76.94 13.06 170.564
92 76.94 15.06 226.804
94 76.94 17.06 291.044
94 76.94 17.06 291.044
98 76.94 21.06 443.524
99 76.94 22.06 486.644
76.93939394 5823.879 sum
181.9962125 = sum /(33-1)= Variance
13.4905971 = (sqrt of Variance) = SD = 13.5
f.How many of the scores are within one standard deviation of the mean?
Those scores between 76.9-13.5 and 76.9+13.5
0r between 63.4 and 90.4 (Quite a number of them)
For the normal distribution:
one standard deviation from the mean accounts for about 68.2% of the set
two standard deviations from the mean account for about 95.4%
and three standard deviations from the mean account for about 99.7%.
Important to Understand z -values as they relate to the Standard Normal curve:
Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.
Note: z = 0 (x value the mean) 50% of the area under the curve is to the left and %50 to the right