Q18. Find the mean for the population

Q19. Find the standard deviation (σ) for the population

Q20. What score (X) corresponds to a z = +0.8?

Q21. What score (X) corresponds to z = -1.64?

Q22. What proportion of the population (answer using 2 decimal places, e.g., 0.45, 0.21)

scored higher than X = 85?

Q23. What proportion of the population (answer using 2 decimal places, e.g., 0.45, 0.21)

scored higher than X = 61?

Q21. What score (X) corresponds to z = -1.64?

Q22. What proportion of the population (answer using 2 decimal places, e.g., 0.45, 0.21)

scored higher than X = 85?

Q23. What proportion of the population (answer using 2 decimal places, e.g., 0.45, 0.21)

scored higher than X = 61?

(I want to figure out the last 4 by myself but I just don't get how to do the first two... sorry if this is a dumb question.)

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