hypothesis testing
Release date: 27 April 2014
Submission date: 9 May 2014
TUTORIAL ON HYPOTHESIS TESTING (1)
Basic Concept
1. State the null and alternative hypothesis for each conjecture :
a. A researcher thinks that if expectant mothers use vitamin pills, the birth weight of the babies will increase. The average birth weight of the population is 3.0kg.
b. An engineer hypothesizes that the mean number of defects can be decreased in a manufacturing process of compact disks by using robots instead of humans for certain tasks. The mean number of defective disks per 1000 is 8.
c. A psychologist feels that playing soft music during a test will change the results of the test. The psychologist is not sure whether the grades will be higher or lower. In the past, the mean score was 73.
d. The average time to read a certain passage is 15 minutes. An educator claimed that a course in speed reading will shorten the reading time.
e. A chemist said that he invested an additive which can increase the life of batter. The mean lifetime is 24 months.
f. The mean waiting bus for buses in Klang Valley is 8 minutes. Some roads are restricted to buses only during office hours. A test is performed to see how this has affected the mean waiting time.
2. Determine whether the one-tailed test or two-tailed test is appropriate for the situation given below:
a. Testing whether the newly-purposed highway speed limit increases the number of accidents.
b. Testing whether the mean weight of chicken changed by breeding with other brand of chicken feed.
c. A manufacturer of brake cables tests to see whether the breaking strength is increased with implementing new technology in manufacturing process
d. A manufacturer of ball-bearings tests to see whether the diameters are correct
3. Find the critical value(s) for each situation below and draw the appropriate figure, showing the critical region.
a. A left-tailed test with α=0.10.
b. A two-tailed test with α=0.02.
c. A right-tailed with
Submission date: 9 May 2014
TUTORIAL ON HYPOTHESIS TESTING (1)
Basic Concept
1. State the null and alternative hypothesis for each conjecture :
a. A researcher thinks that if expectant mothers use vitamin pills, the birth weight of the babies will increase. The average birth weight of the population is 3.0kg.
b. An engineer hypothesizes that the mean number of defects can be decreased in a manufacturing process of compact disks by using robots instead of humans for certain tasks. The mean number of defective disks per 1000 is 8.
c. A psychologist feels that playing soft music during a test will change the results of the test. The psychologist is not sure whether the grades will be higher or lower. In the past, the mean score was 73.
d. The average time to read a certain passage is 15 minutes. An educator claimed that a course in speed reading will shorten the reading time.
e. A chemist said that he invested an additive which can increase the life of batter. The mean lifetime is 24 months.
f. The mean waiting bus for buses in Klang Valley is 8 minutes. Some roads are restricted to buses only during office hours. A test is performed to see how this has affected the mean waiting time.
2. Determine whether the one-tailed test or two-tailed test is appropriate for the situation given below:
a. Testing whether the newly-purposed highway speed limit increases the number of accidents.
b. Testing whether the mean weight of chicken changed by breeding with other brand of chicken feed.
c. A manufacturer of brake cables tests to see whether the breaking strength is increased with implementing new technology in manufacturing process
d. A manufacturer of ball-bearings tests to see whether the diameters are correct
3. Find the critical value(s) for each situation below and draw the appropriate figure, showing the critical region.
a. A left-tailed test with α=0.10.
b. A two-tailed test with α=0.02.
c. A right-tailed with