1. A lecturer claims that the medical students put in more hours studying as compared to other students. The mean number of hours spent on study per week for other students is 23 hours with a standard deviation of 3 hours per week. A sample of 25 medical students was selected at random and the mean number of hours spent on study per week was found to be 25 hours. Can the lecturer's claim be accepted at 5% significance level?

2. College students claim that the cost of living off campus is less than the cost of living on campus. To support the claim, 36 college students who stay off campus were selected at random and their mean expenditure per day is RM 34 with a standard deviation of RM 4. If the mean expenditure of college students staying on campus is RM 35, test the claim at = 0.01.

3. A battery producer claimed that the mean lifetime of a battery produced by his factory was 30 hours. A competitor thought that the figure was too high and took eight batteries at random and later found that the lifetime of each battery was:

Battery	A	B	C	D	E	F	G	H
Lifetime (hours)	15	28	33	24	28	25	31	27

4. A manufacturer of a traditional medicine claims that the medicine is 90% effective in relieving backache for a period of eight hours. In a sample of 200 people who have backache, the medicine provided relief for 160 people. Test the manufacturer's claim at 1% significance level.

5. Umar Pharmacy Limited, a pharmacy company claimed that not more than 1% that used its drug experience side effects. To prove its claim, 2500 patients were subscripted with the drugs and only 74 experienced the sides effects. Can the claim by the Umar Pharmacy Limited be accepted at = 0.05?