In: Statistics and Probability
A task force is studying the need for an additional bicycle path on a large university campus. It is assumed that the distribution of bicyclists using a path between classes is normally distributed with a population variance of about 64. A random sample of 7 existing bicycle paths showed that the sample mean number of bicyclists using a path between classes was 33.
Construct a 95% confidence interval for the population mean number of bicyclists using a bicycle path.
Solution :
Given that,
= 33
2 = 64
= 8
n = 7
At 95% confidence level the z is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2 = Z0.025 = 1.960
Margin of error = E = Z/2* (/n)
= 1.960 * (8 / 7 ) = 6
At 95% confidence interval estimate of the population mean is,
- E < < + E
33 - 6 < < 33 + 6
27 < < 39
(27, 39)