A bicycle factory installs about 400 tires per day. Tires are installed Monday through Friday for 8 hours per day. The manager of the factory estimates the number of properly installed tires per week using the process below. In the first hour of work on Monday, 49 out of 50 tires were properly installed.

So, there were about 8(49) = 392 properly installed tires on Monday.

Considering 5 working days per week, 5(392) = 1,960 is the number of tires properly installed in one week.

Which best explains the validity of the results?
The results are likely invalid because it is unlikely that the tires installed in one hour on Monday will represent the entire population of tires.
The results are likely invalid because the entire population during one week was not part of the sample.
The results are likely valid because a large number of tires produced during the week were part of the sample.
The results are likely valid because each tire sampled was part of the population of tires that week.

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 14, 6, 8, 15, 15. (a) use the defining formula, the computation formula, or a calculator to compute s. (round your answer to one decimal place.) s = 4.28 (b) multiply each data value by 3 to obtain the new data set 42, 18, 24, 45, 45. compute s. (round your answer to one decimal place.) s = 12.83 (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? multiplying each data value by the same constant c results in the standard deviation remaining the same. multiplying each data value by the same constant c results in the standard deviation being |c| times as large. multiplying each data value by the same constant c results in the standard deviation increasing by c units. multiplying each data value by the same constant c results in the standard deviation being |c| times smaller. (d) you recorded the weekly distances you bicycled in miles and computed the standard deviation to be s = 3.8 miles. your friend wants to know the standard deviation in kilometers. do you need to redo all the calculations? yes no given 1 mile ≠1.6 kilometers, what is the standard deviation in kilometers? (enter your answer to two decimal places.)