b. false
3. A certain group of students study two and half hours per week with a standard
deviation of half an hour. If a random sample of 25 students is taken, what is the
probability they studied less than 2.25 hours. Let X = the number of hours a
student studied.
a. (1 pt) Provide the formula for calculating the Z-score
b. (2 pts - Show your work) Calculate the Z-score
C. (1 pt) State the probability mathematically.
d. (1 pt) State the Excel function you will use to calculate the probability.
e. (2 pts) Use your calculated z-score to find the probability,​

Respuesta :

Answer:

Step-by-step explanation:

a)  P(0 ≤ Z ≤ 2.25)

b) Let standard deviation, α = 0.5; random variable, X = 2.25; mean, U = 1

By comparing P(0 ≤ Z ≤ 2.25)

P(Z ≤ X - U/α) = P(Z ≤ 2.25 - 1/0.5)

P(Z ≤ 2.5)

Z - score = 2.5

C)  Probability, P(Z ≤ 2.5)

e) Using table

P(0 ≤ Z ≤ 2.5) = 0.4938