1. Your candidacy for elected class representative is being opposed by Slick Sally. Your election committee has surveyed six of the students in your class and had them rank Sally on a scale of 010. The rankings were

2, 8, 7, 10, 9, 8.

(a) Find the sample mean and standard deviation. HINT [See Example 1 and Quick Examples 1 and 2.] (Round your answers to two decimal places.)

sample mean :

standard deviation :

(b) Assuming that the sample mean and standard deviation are indicative of the class as a whole, in what range does the empirical rule predict that approximately 95% of the class will rank Sally? (Include only practical values in your interval. Round your answers to two decimal places.)

[ , ]

What other assumptions must we make to use the rule?

A. The population distribution is bell-shaped and symmetric.

B. The population distribution is symmetric, but not bell-shaped.

C. The population distribution is bell-shaped, but not symmetric.

D. The population distribution is neither bell-shaped nor symmetric