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Find the range of distinction cutoffs
The marks of a large number of examination candidates are normally distributed with mean 45 and standard deviation 10. A candidate obtains a distinction by scoring x marks or more. If less than 5% obtain a distinction, find the range of x, correct to 1 decimal place.
CJC · Lecture · Example 4
Identify the mean and take the square root of the variance.
Convert the event to an interval and sketch the shaded area.
Use normalcdf with lower bound, upper bound, mean and standard deviation in that order.