Answer:
Mean: 40.17 years.
Standard deviation: 10.97 years.
Step-by-step explanation:
The frequency distribution is in the attached image.
We can calculate the mean adding the multiplication of midpoints of each class and frequency, and dividing by the sample size.
The midpoints of a class is calculated as the average of the bounds of the class.
Then, the mean can be written as:
The standard deviation can be calculated as:
Answer:
The probability that the pitcher throws exactly 8 strikes out of 15 pitches is approximately 0.199
Step-by-step explanation:
The given probability that the pitcher throws a strike, p = 0.507
The number of pitches thrown by the pitcher = 15 pitches
The probability that the pitcher does not throw a strike, q = 1 - P
∴ q = 1 - 0.507 = 0.493
By binomial theorem, we have;
When X = r = 8, and n = 15, we get;
The probability that the pitcher throws exactly 8 strikes out of 15 pitches, P(8), is given as follows
P(8) = ₁₅C₈ × 0.507⁸ × (1 - 0.507)⁽¹⁵ ⁻ ⁸⁾ = 6,435 × 0.507⁸ × 0.493⁷ ≈ 0.199