Question

Find the standard? deviation, s, of sample data summarized in the frequency distribution table below by using the formula? below, where x represents the class? midpoint, f represents the class? frequency, and n represents the total number of sample values.? Also, compare the computed standard deviation to the standard deviation obtained from the original list of data? values, 11.1. sequalsStartRoot StartFraction n left bracket Summation from nothing to nothing left parenthesis f times x squared right parenthesis right bracket minus left bracket Summation from nothing to nothing left parenthesis f times x right parenthesis right bracket squared Over n left parenthesis n minus 1 right parenthesis EndFraction EndRoot Interval 30?-39 40?-49 50?-59 60?-69 70?-79 80?-89 90?-99 Frequency 1 2 3 2 9 35 35 Standard deviationequals nothing ?(Round to one decimal place as? needed.) Consider a difference of? 20% between two values of a standard deviation to be significant. How does this computed value compare with the given standard? deviation, 11.1?? A. The computed value is not significantly different from the given value. B. The computed value is significantly less than the given value. C. The computed value is significantly greater than the given value.

Answer 1

Result:

Find the standard? deviation, s, of sample data summarized in the frequency distribution table below by using the formula? below, where x represents the class? midpoint, f represents the class? frequency, and n represents the total number of sample values.? Also, compare the computed standard deviation to the standard deviation obtained from the original list of data? values, 11.1. sequalsStartRoot StartFraction n left bracket Summation from nothing to nothing left parenthesis f times x squared right parenthesis right bracket minus left bracket Summation from nothing to nothing left parenthesis f times x right parenthesis right bracket squared Over n left parenthesis n minus 1 right parenthesis EndFraction EndRoot Interval 30?-39 40?-49 50?-59 60?-69 70?-79 80?-89 90?-99 Frequency 1 2 3 2 9 35 35

Standard deviation equals 12.6 (Round to one decimal place as? needed.)

Consider a difference of? 20% between two values of a standard deviation to be significant. How does this computed value compare with the given standard? deviation, 11.1??

Difference : 12.6-11.1=1.5

Difference % = 1.5*100/11.1 = 13.5

Answer: A. The computed value is not significantly different from the given value.

B. The computed value is significantly less than the given value.

C. The computed value is significantly greater than the given value.

	f	mid x	f*x	f*x*x
30-39	1	34.5	34.5	1190.25
40-49	2	44.5	89	3960.5
50-59	3	54.5	163.5	8910.75
60-69	2	64.5	129	8320.5
70-79	9	74.5	670.5	49952.25
80-89	35	84.5	2957.5	249908.8
90-99	35	94.5	3307.5	312558.8
	87	Total	7351.5	634801.8

=12.5754