You’re going to use your ti-83 graphing calculator to compute the area between values of 7 and 9 for a distribution whose mean is 8 and whose standard deviation is 2. you would enter:

a) normalcdf (7,9,8,2)
b) normalpdf (7,9,8,2)
c) invnorm (8,7,9)
d) normalcdf (8,2,7,9)
e) normalpdf (8,2,7,9)

The answer is A

Step-by-step explanation: You use normalcdf to find the area under a curve. The lower bound (in this case 7) goes first followed by the upper bound, mean, and standard deviation.

Solved using binomial, probability = 5.7%

Step-by-step explanation:

Number of people (N) = 7

Probability of success (using phone) = 63% = 0.63

So, probability of failure (not using phone) = 1 - 0.63 = 37

Number of success (r) = 2

N c r . P^r . Q^n-r

7 c 2 (0.63)^2 (0.37)^5

= 21 (0.3969) (0.0069)

= 0.057