## Related questions with answers

Bjork Larsen was trying to decide whether to use a new racing wax for cross-country skis. He decided that the wax would be worth the price if he could average less than 55 seconds on a course he knew well, so he planned to study the wax by racing on the course 8 times. His 8 race times were 56.3, 65.9, 50.5, 52.4, 46.5, 57.8, 52.2, and 43.2 seconds. Should he buy the wax? Explain by using a confidence interval

Solution

VerifiedGiven:

$c=\text{Confidence level}=95\%=0.95\:\:\:\:\: \color{#4257b2}(\text{Assumption})$

DESCRIPTIVE MEASURES

The mean is the sum of all values divided by the number of values:

$\overline{x}=\dfrac{56.3+65.9+50.5+52.4+46.5+57.8+52.2+43.2}{8}=\dfrac{53.1}{8}=53.1$

$n$ is the number of values in the data set.

$n=8$

The variance is the sum of squared deviations from the mean divided by $n-1$. The standard deviation is the square root of the variance:

$s=\sqrt{\dfrac{(56.3-53.1)^2+....+(43.2-53.1)^2}{8-1}}\approx 7.0285$

## Create an account to view solutions

## Create an account to view solutions

## Recommended textbook solutions

#### Stats: Data and Models

5th Edition•ISBN: 9780135163825 (1 more)David E. Bock, Paul Velleman, Richard D. De Veaux#### Probability and Statistics for Engineers and Scientists

9th Edition•ISBN: 9780321629111 (9 more)Keying E. Ye, Raymond H. Myers, Ronald E. Walpole, Sharon L. Myers#### The Practice of Statistics for the AP Exam

5th Edition•ISBN: 9781464108730Daniel S. Yates, Daren S. Starnes, David Moore, Josh Tabor#### Statistics and Probability with Applications

3rd Edition•ISBN: 9781464122163Daren S. Starnes, Josh Tabor## More related questions

1/4

1/7