Answer: Let's first find the expected value or the mean number of questions Jack would correctly guess:
Expected value = mean = n * p = 7 * 0.74 = 5.18
where n is the number of trials (7) and p is the probability of success (0.74).
The variance of the number of correct guesses is given by:
Variance = n * p * (1 - p) = 7 * 0.74 * (1 - 0.74) = 1.7
The standard deviation is the square root of the variance:
Standard deviation = sqrt(Variance) = sqrt(1.7) ≈ 1.30
Therefore, the standard deviation for the number of questions Jack would correctly guess is approximately 1.30.
Explanation: