BBM203/03: David set a mathematics quiz for his students The quiz is marked out of 10 His students’ marks are summarized: Business Statistics Assignment, WOU, Malaysia

• Prob (A)
• Prob (University graduate)
• Prob (A University graduate)
• Prob (University graduate A)

Part 2

The random variable Y follows a normal distribution with mean µ and variance σ² , i.e. Y  N(µ, σ²). Suppose we have the following information:

P(X ≤ 66) = 0.0421 and P(X ≥ 81) = 0.1298

(a) Compute the value of σ = 5

(c) Calculate P(65 ≤ X ≤ 74)

Question 4

• A sample of test scores is obtained. The scores are displayed as follows:

11, 16, 19, 15, 7, 8, 10

Test the hypothesis that the mean score is 15 at a 1% significance level

• A chemical manufacturer is concerned about the degree of contamination in the raw material shipments purchased from a supplier. Taking a random sample of 20 shipments of raw materials, the standard deviation of contamination is 3.59. Construct the 95% confidence interval for population variance.