Few years ago the average number of hours worked each week

Question

Questions-

I. Few years ago, the average number of hours worked each week by general practitioners was known to be 49.  A random sample of 29 general practitioners this year gives a mean of 52 hours per week, with a standard deviation of 4.3 hours.  To test if the number of hours worked per week has increased, which of the following hypotheses are correct?

a. H₀: μ = 49 vs H_A: μ ≠ 49
b. H₀: μ = 49 vs H_A: μ > 49
c. H₀: μ = 49 vs H_A: x¯ = 52
d. H₀: x¯ = 52 vs H_A: x¯ > 52
e. H₀: x¯ = 52 vs H_A: x¯ ≠ 52

II. How can you avoid making a Type I error in a hypothesis test? 

III. Suppose a researcher conducts an experiment to test a hypothesis. If he doubles his sample size, which of the following will increase? Explain why? 

a. The power of the hypothesis test. 
b. The effect size of the hypothesis test. 
c. The probability of making a Type II error. 

1) (a) only 
2) (b) only 
3) (c) only 
4) all of the above 
5) none of the above

Additional information-

These questions related to Basic Statistics and they are multiple choice questions which deal with the average working hours of general practitioners, doubling the sample size and avoiding Type I error in hypothesis tests.