Question

A research analyst disputes a trade group’s prediction that back-to-school spending will average $622 per family this year. She believes that average back-to-school spending will significantly differ from this amount. She decides to conduct a test on the basis of a random sample of 35 households with school-age children. She calculates the sample mean as $637. She also believes that back-to-school spending is normally distributed with a population standard deviation of $68. Calculate the test statistic. Keep three decimals

Answer 1

Solution :

= 622

=637

=68

n = 35

This is the two tailed test .

The null and alternative hypothesis is ,

H0 :    = 622

Ha :     622

Test statistic = z

= ( - ) / / n

= (637-622) / 68 / 35

= 1.305

Test statistic = z = 1.305