6.2.75 z-score

Use a standard normal distribution table to obtain the​ z-score that has an area of 0.99 to its right.

Put the area to the left into qnorm(), it returns z-score

Since we have the area to the right

qnorm(1-.99)

## [1] -2.326348

Round to two decimal places using round() command

round(qnorm(1-.99),2)

## [1] -2.33

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Hope that helps!