Question

In an experiment related to "fast starts" — the acceleration and speed of a hockey player from a stopped position — sixty-eight hockey players, varsity and intramural, from a local university were required to move as rapidly as possible from a stopped position to cover a distance of 6 meters. The means and standard deviations of some of the variables recorded for each of the 68 skaters are shown in the table.

	Mean	SD
Weight (kilograms)	74.270	9.370
Stride Length (meters)	0.910	0.235
Stride Rate (strides/second)	3.210	0.370
Average Acceleration (meters/second2)	2.862	0.579
Instantaneous Velocity (meters/second)	5.653	0.942
Time to Skate (seconds)	1.753	0.031

(a)

Give the formula that you would use to construct a 98% confidence interval for one of the population means (for example, mean stride length).

Construct a 98% confidence interval for the mean stride length. (Round your answer to three decimal places.)

(c)

Interpret this interval.

We are 98% confident that the population mean stride length is directly in the middle of these two values.

There is a 98% probability that the population mean stride length is within the interval.    

There is a 98% probability that the mean stride length for the sample is within the interval.

We are 98% confident that the population mean stride length is within the interval.

We are 98% confident that the mean stride length for the sample is within the interval.

Answer 1

For, Stride length

Mean = 0.910, SD = 0.235, n = 68, = 0.02

a)

98% Confidence interval:

b)

Critical value:

Z /2 = Z0.02/2 = 2.33          ...................Using standard Normal table

98% Confidence interval:

C)

ANSWER: C

We are 98% confident that the population mean stride length is within the interval.