A rental agent claims that the mean monthly rent, u , for apartments on the east side of town is less than $675. A random sample of 21 monthly rents for apartments on the east side has a mean of $674, with a standard deviation of $18. If we assume that the monthly rents for apartments on the east side are normally distributed, is there enough evidence to conclude, at the 0.1 level of significance, that u is less than $675?

Perform a one-tailed test.
null hypothesis:
alternative hypothesis?
type of test statistic?
Critical value at the 0.1 level of significance?
Using the 0.1 level of significance, can we conclude that the mean monthly rent for apartments on the east side is less that $675?