1. a normal distribution of scores has a standard deviation of 10. find the z-scores corresponding to each of the following values: a) a score that is 20 points above the mean. b) a score that is 10 points below the mean. c) a score that is 15 points above the mean d) a score that is 30 points below the mean. 2. the welcher adult intelligence test scale is composed of a number of subtests. on one subtest, the raw scores have a mean of 35 and a standard deviation of 6. assuming these raw scores form a normal distribution:

Answer with Step-by-step explanation:

The Z score in a distribution is found as

where

X is the given value

is the mean of the observations

is the standard deviation of the data

The values of oach part is found as under:

Part a)

Since it is given that score is 20 points over mean thus we can write

Using the above relation we get

Part b)

Since it is given that score is 10 points below mean thus we can write

Using the above relation we get

Part c)

Since it is given that score is 15 points over mean thus we can write

Using the above relation we get

Part d)

Since it is given that score is 30 points below mean thus we can write

Using the above relation we get

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step-by-step explanation:

12cm

the answer is d