Question

A penny tossed 120 times results in 62 heads and 58 tails.
a. Calculate the expected number of heads and tails and determine the percent deviation.

Answer 1

Expected number of heads = (total number of tosses * probability of getting a head) = 120 * 0.5 = 60

Expected number of tails = (total number of tosses * probability of getting a tail) = 120 * 0.5 = 60

Percent deviation for heads = ((observed number of heads - expected number of heads) / expected number of heads) * 100
= ((62 - 60) / 60) * 100
= (2 / 60) * 100
= 3.33%

Percent deviation for tails = ((observed number of tails - expected number of tails) / expected number of tails) * 100
= ((58 - 60) / 60) * 100
= (-2 / 60) * 100
= -3.33%

Therefore, the expected number of heads is 60, whereas the percentage deviation is 3.33%.
The expected number of tails is 60, whereas the percentage deviation is -3.33%.