Question

A study of 45 members of the Mall Walkers group showed that they could walk at an average rate of 3.3 miles per hour. A previous study showed that the standard deviation is 1.0 miles per hour. Make a 90% confidence interval statement for the mean walking speed for all members I am 90% confident that the mean walking speed for mall walkers is between 3.0495 mph and 3.5505 mph. I am 90% confident that the mean walking speed for mall walkers is between 0.19084 mph and 1.8092 mph. OI am 90% confident that the mean walking speed for mall walkers is between 3.0548 mph and 3.5452 mph. OI am 90% confident that the mean walking speed for mall walkers is between 0.17344 mph and 1.9266 mph.

Answer 1

Given,

$\small \mu = 3.3$

$\small \sigma = 1$

$\small n=45$

The confidence interval is given by,

o Confidence Interval = 2*

where, z score for 90% confidence level is 1.64

$\small Confidence\; Interval = 3.3 \pm 1.64 * \frac{1} {\sqrt{45}}$

$\small Confidence\; Interval = [3.0548 \; , \; 3.5452]$

Therefore,

We are 90% confidence that the mean walking speed for mall walkers is between 3.0548 mph and 3.5452 mph