Question

Critical Thinking: Data Transformation In this problem, we explore the effect on the standard deviation of multiplying each data value in a data set by the same constant. Consider the data set 5, 9, 10, 11, 15.
(a) Use the defining formula, the computation formula, or a calculator to compute s.
(b) Multiply each data value by 5 to obtain the new data set 25, 45, 50, 55, 75. Compute s.
(c) Compare the results of parts (a) and (b). In general, how does the standard deviation change if each data value is multiplied by a constant c?
(d) You recorded the weekly distances you bicycled in miles and computed the standard deviation to be s 3.1 miles. Your friend wants to know the standard deviation in kilometers. Do you need to redo all the calcula- tions? Given 1 mile 1.6 kilometers, what is the standard deviation in kilometers?

Answer 1

Answer:

Kindly check explanation

Step-by-step explanation:

Given the data : 5, 9, 10, 11, 15

s = √[(ΣX - m)² / (n - 1)]

n = number of sample = 5

m = mean

m = ΣX/n

m = (5 + 9 + 10+ 11 + 15) / 5

m = 50/5 = 10

s =√((5-10)^2 + (9-10)^2 + (10-10)^2 + (11-10)^2 + (15-10)^2) / 5-1

= 3.601

(B) Multiply each data value by 5 to obtain the new data set 25, 45, 50, 55, 75. Compute s.

m = ΣX/n

m = (25 + 45 + 50 + 55 + 75) / 5

m = 250/5 = 50

s =√((25-50)^2 + (45-50)^2 + (50-50)^2 + (55-50)^2 + (75-50)^2) / 5-1

= 18. 028

(c) Compare the results of parts (a) and (b). In general, how does the standard deviation change if each data value is multiplied by a constant c?

The standard deviation changes by almost c times multiplied by the initial value.

3.601 * 5 = 18.005 which is almost equivalent to 18.028

(d) You recorded the weekly distances you bicycled in miles and computed the standard deviation to be s 3.1 miles. Your friend wants to know the standard deviation in kilometers. Do you need to redo all the calcula- tions?

No

Given 1 mile 1.6 kilometers, what is the standard deviation in kilometers?

If 1 mile = 1.6km

s = 3.1 miles

s in kilometers = (1.6 * 3.1) = 4.96km