Question

(1 point) Suppose we will flip a fair coin 100 times. (a) What does 35 heads correspond to on the standard scale? (enter exact answer) (b) What does z=2.4 on the standard scale correspond to on the number of heads scale? (enter exact answer)

Answer 1

Answer:

(a) 35 heads correspond to -3 on the standard scale.

(b) z = 2.4 corresponds to 62 heads on the number of heads scale.

Step-by-step explanation:

(a) If we flip a fair coin once, probability of getting head = 0.5

If we flip a fair coin 100 times, mean number of heads = 100(0.5) = 50

If there are N draws with a P probability of success, the standard deviation (SD) is given as:

$SD = \sqrt{(N)(P)(1 - P)}$

Here, the probability of getting a head (P) is 0.5 while the number of draws (N) is 100. So,

$SD = \sqrt{(100)(0.5)(1-0.5)}$

SD = 5

The standard scale value is: (35 - 50) / 5 = -3

Hence, 35 heads correspond to -3 on the standard scale.

(b) The standard scale value is 2.4 and we need to find the number of heads.

(X - 50) / 5 = 2.4

X - 50 = 12

X = 62

Hence, z = 2.4 on the standard scale corresponds to 62 on the number of heads scale.