Assume that we want to construct a confidence interval. Do one of

the following, as appropriate. (a) Find the critical value Za/2. (b) find the critical

value ta/2, or (c) state that neither the normal nor the t distribution applies.

Confidence level is 95%, o = 26.6, and the histogram of right-eye vision

measurements from a random sample of 66 adult males is shown to the right.

Frequency

40

30-

20

10

of

0

50 100 150 200

Vision in Right Eye

Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

OA. Za/2

(Round to two decimal places as needed.)

OB. ta/2

(Round to two decimal places as needed.)

OC. Neither the normal nor the t distribution applies.

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