FREE AND STUDY GAMES ABOUT STATS EXAM 2

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FREE AND STUDY GAMES ABOUT STATS EXAM 2

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -86 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: Independent samples t-test

Answer:

Used to compare two means in a between-groups design (each participant is only in one condition) Question 2: Confidence interval: How to turn the z-statistic into raw scores

Answer:

Mlower=Msample-z(?M) Mupper=Msample+z(?M) *z=1.96* Question 3: When given data; subtract the mean from every x, and square each value to get the....

Answer:

Sum of squares Question 4: A study reports finding a "significant" difference between group means. What can be concluded about this report?

Answer:

To fully assess the importance and impact of the results, we must also have information about the spread of the distributions

Question 5: If the mean from a sample falls in the tail of a sample distribution, we conclude...

Answer:

that it didn't come from the sample

Question 6: Paired-samples t test

Answer:

Measure performance on two different occasions and compare difference; within-groups design Question 7: Independent samples: standard error

Answer:

sdifference= the square root of s²difference

Question 8: Homogeneity of variance

Answer:

The two populations from which samples are selected must have equal variances... as long as larger variance isn't twice the size of small variance.Fmax=s²(largest)/s²(smallest)

Question 9: Calculating power is useful

Answer:

Before a study. Because after, if you fail to reject the null, you know you didn't have enough power and if you reject the null power doesn't matter because you're happy with your results.

Question 10: Dot plot

Answer:

A graph that displays all the data points in a sample, with the range of scores along the x-axis and a dot for each data point above the appropriate value.Question 11: With a large enough sample size, even a very small difference in data...

Answer:

can fall in the rejection, or critical region (a number that falls in the confidence interval with a sample size of 6 might be fall in the tail with a sample size of 49)

Question 12: The t statistic is more _____ than the z statistic because one is less likely to observe an extreme t statistic.

Answer:

conservative

Question 13: Calculating confidence intervals

Answer:

• Draw a distribution around the sample mean

• Indicate bounds on your drawing (-1.96 and 1.96)

• Mark the middle 95%

• Turn the z-statistic into raw scores

• Check

Question 14: Type 1 error

Answer:

We reject the null hypothesis but the null hypothesis is actually correct

Question 15: Larger effect size=

Answer:

Less overlap

Question 16: Critical region for 95% confidence interval

Answer:

1.96 and -1.96 for z-tests, and critical values for df in t-tests

Question 17: Critical value for t-statistic

Answer:

Look up the df in table in .05 two tailed test column

Question 18: Wasting time if power is below

Answer:

.8 (80%)

Question 19: Statistical power can be enhanced by decreasing the standard deviation in the

sample. This can be accomplished by:

Answer:

Sampling a more homogenous group, working a narrower, less variable, distribution of scores, and using a more reliable measure.Question 20: If the treatment has a very small effect, then what is the likely outcome for a hypothesis test evaluating the treatment?

Answer:

A type 2 error

Question 21: p<.05

Answer:

Significant (rejected null) The probability is small that the relationship or difference happened by chance

Question 22: Type 2 error

Answer:

We fail to reject the null hypothesis but the null hypothesis is actually incorrect

Question 23: Advantages of a within-groups design

Answer:

Distribution of mean differences, smaller sample size is ok, reduced variability, more power

Question 24: Null hypothesis for a single sample t-test

Answer:

?=x Question 25: Two samples drawn from the same population will probably have _____ t-statistics even if they're the same size and have the same mean

Answer:

Different; each sample has a different standard deviation.Question 26: Independent samples: s²difference=

Answer:

s²Mx+s²My