Part 3: Data Distributions Flashcards Preview

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Flashcards in Part 3: Data Distributions Deck (8)
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1
Q

What is the non-linear transformation we apply to each value?

Moderate pos+ skewed data:

Substantially pos+ skewed data:

Severely pos+ skewed data:

A

Moderate pos+ skewed data:

Square root

Substantially pos+ skewed data:

Log (x)

Severely pos+ skewed data

1/x

2
Q

In a z-scores table, what are the z-scores for the upper and lower 5%?

A

-1.64 and +1.64

3
Q

What percentage or scores are within +/- 1.96 SD’s of the mean?

A

95%

4
Q

What percentage of scores are within +/- 2.58 SD’s of the mean?

A

99%

5
Q

95% of data lies within __ SD’s of the mean.

A

95% of data lies within 2 SD’s of the mean.

6
Q

How do we measure the extent to which a sample mean differs from the population mean?

I.e. The amount by which we are likely to error when estimating the population mean from the sample mean.

A

Compute the Standard Error of sample means.

Variance / square root of n.

7
Q

What are the 3 assumptions of the Central Limit Theorem?

A
  1. The distribution of all sample means, will have a mean equal to the population mean.
  2. The distribution of all means, will have a SD equal to the SE.
  3. As the sample size (N) increases, the distribution of sample means will become closer to the population mean.
8
Q

In SPSS, the skewness statistic must be greater than __ to qualify for a non-linear transformation.

A

In SPSS, the skewness statistic must be greater than 2 to qualify for a non-linear transformation.