MATH 227 STATISTICS FINAL EXAM - West Los Angeles College

M227 Fall 2006 FINAL EXAM NAME:______________
Thursday, June 7, 2007 11:30AM-1:30PM
Instructor: M. Robertson
Directions: Use the SCANTRON form for all problems 1-100. Show all of your work in the test
booklet. You may use your calculator, but indicate what you did. Good luck! You have 2 hours.
1-45) TRUE(A) or FALSE(B) 1 point each
1. For any two events A and B, PA ( ∪ B) = PA ( ) + PB ( ) −PA ( ∩ B)
.
2. If two events A and B are mutually exclusive, then PA ( ∩ B) = PA ( ) × PB ( ).
3. Zip codes are an example of numerical (not categorical) data.
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4. The Chi-Squared χ test statistic is used to perform a hypothesis test on σ (or on σ ).
5. For a data set having a positively skewed unimodal histogram, the median will be to the right
of the mean.
6. In a sample of size 25, the median is the average of the 12th and 13th largest values.
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7. The variable χ is normally distributed.
8. For any continuous probability distribution, P ( x = c)
= 0 for all values of c .
9. For a standard normal distribution, and for some point a on the number-line,
P ( z < −a)
= P(
z > a)
.
10. If the null hypothesis is not rejected, then there is strong statistical evidence that the null
hypothesis is absolutely true.
11. In the multiple regression model y = β0 + β1x1+ β2x2, β
2
can be interpreted as the amount
y will be expected to change when the value of the predictor variable x 2
is increased by one unit,
as long as the predictor variable x 1
is held constant.
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