Hypothesis and different stats

Question 1

What does it mean when we say that the sample mean is plausible (logical/credible)?

Answer 1

It means that it lies within a normal distribution/ normally distributed. If not plausible, then the null hypothesis is false.

Question 2

What is central limit theorem?

Answer 2

Sampling distribution of the sample means approaches a normal distribution as the same gets larger and these means will be distributed around population mean

Question 3

Estimation of where the sample mean falls relative to population mean depends on?

Answer 3

1. Sample size

2. an estimate of the population variance

Question 4

The smaller the p-value, the more statistical evidence exists to support the alternative hypothesis.
Please name the range.

Answer 4

1. less than 1 % - overwhelming evidence
2. 1- 5% - strong evidence
3. 5 - 10% - a trend / weak evidence
4. Over 10% - no evidence to support H1

Question 5

What is Type 1 and 2 error?

Answer 5

Type 1 = accepting H1 (rejecting H0) wrongly : false positive
Type 2 = accepting H0 (rejecting H1) wrongly: false negative

Question 6

Z value and rejection region

Answer 6

The region where u can use to reject H0

Question 7

What are the criticisms to H0?

Answer 7

Significant effect does not mean big effect size

Question 8

ADvantages of effect size?

Answer 8

Allows researchers to come to a common metric for evaluating a divers experiment.

Question 9

How does cohen’s D measure the mean difference?

Answer 9

using SD

Question 10

Size of effect for Cohen’s D? and for Pearson’s correlation?

Answer 10

1. Cohen’s D : 2, 5, 8

2. 1, 3, 5

Question 11

What is power of a hypothesis test?

Answer 11

The power of a hypothesis test is defined as the probability that the test will reject the null hypothesis when the treatment
does have an effect (rule of thumb: minimum of 80%).

Question 12

What does power of test depends on?

Answer 12

Alpha level, sample size and effect size

Question 13

When H0 is true and u reject = alpha
when H1 is true and u accept H0 = beta
when H1 is true and u reject H0 = 1 - beta

Answer 13

NIL

Question 14

What is SE (and therefore SEM)

Answer 14

SE shows how accurate ur sample mean is compared to population mean.

Question 15

Principles of Central limit theorem?

Answer 15

1. Sample mean (s) = population mean
2. SD of sample mean = SE
3. For large sample , mean distribution is normal even if the distribution of samples drawn from this population is not normal.

Question 16

How do you calculate the probability of observation 1 and observation 2?

Answer 16

P (A and B) = P(A) x P (B)

Imagine all 4 cups are right
• What is the probability of this outcome?
• What is the probability of getting the first cup right?
• P (4 correct guesses) =
4/8 x 3/7 x 2/6 x 1/5 = 0.014

Question 17

P values assume that H0 is true and it allows statement of the data and not theory

Answer 17

NIL

Question 18

a p value of < 0.5 doesn’t mean no effect, it could be that that the effect is too small to be observed

Answer 18

NIL

Question 19

What is power of 80% means?

Answer 19

80% of the chances to detect a true effect or 80% chances p value falls under 0.05

Question 20

What does p value distribution depends on?

Answer 20

Statistical power (power to detect true effect) and power depends on sample size

Question 21

Sensitivity and specificity in terms of H0 and H1?

Answer 21

Sensitivity - Reject H0 when H0 is false

Specificity - Accept H0 when H0 is true

Question 22

What is probability as propensity?

Answer 22

Comparing different likelihoods of outcome given a current data OR

tendency of a given type of physical situation to yield an outcome of a certain kind, or to yield a long run relative frequency of such an outcome

Question 23

what is probability in Bayesian analyses?

Answer 23

Strong prior beliefs, see new things update belief but new data is always actively being compared to prior belief.

Question 24

The more tests we do with only ONE data set (not replication), more errors and have to correct using Multiple Comparison

Answer 24

NIL