BA 210 Business Statistics for Business & Economics Professor Ji University of Guam Summer
Intersession 2018
Exam 4
Students are required to submit the completed exam as a separate answer sheet using
Excel. Show ALL work or where indicated (On subsequent EXCEL sheets) or no credit
will be given. Name of document should be “210.lastname.e4”. GOOD LUCK!
True / False Questions (1 pt. each) No work needs to be shown for this section
1) Alpha is the risk of not rejecting the null hypothesis when it is actually
true. True False
2) If the null hypothesis is false and the researchers do not reject it, then a
Type II error has been made. True False
3) A p-value is the same as a stated (alpha) significance level.
True False
4) The probability of a Type II error is represented by the Greek symbol, .
β
5) In testing the difference between two population proportions, we pool the
two sample proportions to estimate the population proportion. True False
6) The pooled estimate of the proportion is found by dividing the total
number of samples by the total number of successes. True False
7) When the population standard deviations are equal but known, a test for
the differences between two population means has n2 - 2 degrees of freedom. True False
Multiple Choice Questions (1 pt. ea.) Show ALL work for this section
8) A manufacturer wants to increase the lead-time to get items delivered.Past records indicate that the average lead-time is 216 days. After a new process has been utilized, a sample of nine times shipped had lead times (in days): 215, 215, 216, 215, 215, 216, 216, 216 and 215. At the 0.01 level, has the lead time of items decreased?
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- Summer '16
- Statistics, Null hypothesis, significance level
