PLS 209 Research Methods
Name______________________
Homework5 Normal Curve
For a normal distribution with a mean of
25 and a standard
deviation of 5:
1. and 2. Calculate the Z scores and then look up the
area under the standard
form of the normal curve for the following values from the above distribution:
Value
10,
15.2, 20,
25, 30,
32.5, 34.8,
40
-2.0 -1.96
-1.0 0
1.0 1.50
1.96 3.0
Z-score ______
______ ______ ______ ______ ______ ______
______
Area ______ ______ ______ ______ ______ ______
______ ______
3. What proportion of cases will have values between
25 and 40
4. What proportion of cases will have values between 10
and 40?
5. What proportion of cases will have values between
30 and 40?
6. What proportion of cases will have values less
than 15.2?
7. What proportion of cases will have values between
15.2 and 34.8?
8. If you randomly select a case from this distribution, how
many times out of 100 will you get a
value
a. Less than 15.2 _________
b. Greater than 34.8 _________
c. Greater than 15.2 and Less than 34.8? _________
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