Question

(Choose Best Option)

1) The probability of a type I error increases when:
a) Significance is lowered
b)   The number of samples is lowered
c)   Using two-tailed t-test rather than a one-tailed t-test
d)   Multiple pair-wise comparisons are performed
 
2) A population has a mean weight of 70 kg with a standard deviation of 5 kg. The weight of a sample of N = 100 subjects were taken.

The following statement is false:
a)   95% of the people in the population have a weight between 60 kg and 80 kg
b)   There is a 95% probability that the sample mean is between 69 kg and 71 kg
c)   There is a 95% probability that the sample mean is between 69.5 kg and 71.5 kg
d)   The mean of the sampling distribution of the mean is exactly 70 kg.

3) The following statement is true:
a)   It is easier to reject the null hypothesis if the researcher uses a smaller alpha (α) level
b)   You are more likely to make a Type I error when using a small sample than when using a large sample
c)   You accept the alternative hypothesis when you reject the null hypothesis
d)   As the sample size gets larger, the probability that the confidence interval will contain the population mean gets higher

4) The following statement is true:
a)   The probability value is the probability that the null hypothesis is false.
b)   A researcher risks making a Type I error any time the null hypothesis is rejected
c)   A low probability value indicates a large effect.
d)   A non-significant outcome means that the null hypothesis is probably true.

5) The following increases power of a statistical test:
a)   A smaller sample size
b)   A higher population variance
c)   A higher alpha value
d)   Using two-tailed t-test rather than a one-tailed t-test

6) A paired t-test yields a p-value of p = 0.0001. Using this knowledge, the following is true:
a)   There is large difference between the means of the two conditions
b)   The null hypothesis is false
c)   There is a high probability that the alternate hypothesis is true
d)   The test has high power
 

Answer 1

1) The probability of a type I error increases when:

( This is alpha value and increases if ):

d)   Multiple pair-wise comparisons are performed
 

2) A population has a mean weight of 70 kg with a standard deviation of 5 kg. The weight of a sample of N = 100 subjects were taken.

a)   95% of the people in the population have a weight between 60 kg and 80 kg

( this is wrong interpretation of confidence interval )

3) The following statement is true:

c)   You accept the alternative hypothesis when you reject the null hypothesis

( As you can onlu claim one of the two correct )

4) The following statement is true:

d)   A non-significant outcome means that the null hypothesis is probably true.

Usually null hypothesis assumes value = 0 ( non significance )

5) The following increases power of a statistical test:

c)   A higher alpha value

As the alpha increase the power of the test increases

6) A paired t-test yields a p-value of p = 0.0001. Using this knowledge, the following is true:

c)   There is a high probability that the alternate hypothesis is true

Probability of rejection of null hypothesis is higher as p = 0.0001