Stats Flashcards

1
Q

True or false

A Z-distribution belongs to the normal distribution family and serves as the standard by which other normal distributions are evaluated.

A

True

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2
Q

Describe a normal distribution

A

The standard deviation represents the distance from the mean to its inflection points,

The mean and median are identical

 It is symmetrical

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3
Q

A Z-distribution is also called

A

Standard scores, Z scores, Z values

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4
Q

What does a Z score represent?

A

The number of standard deviation instead of value lies above or below the mean

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5
Q

True or false

Standardizing does not change the probabilities of X; it only changes units

A

True

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6
Q

The process of standardizing converts what to what?

A

Convert an X-value to Z-value

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7
Q

A Z- distribution is normally distributed with a mean of _______ and standard deviation of ________

A

Mean of 0 and standard deviation of 1

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8
Q

What percent of a normal distribution lies within 1 standard deviation of the mean

A

68%

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9
Q

What percent of the normal curves values lie within 2 standard deviations of the mean

A

95%

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10
Q

What percent of a normal curves values fall within 3 standard deviations of the mean

A

99.7%

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11
Q

Almost all (99.7%) of a normal curves value falls within ______ standard deviations of the mean.

A

3

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12
Q

True or false

Standardizing does not change the probabilities for X; it only changes units

A

True

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13
Q

About _____ percent of the normal curves, values lies within two standard deviations of the mean

A

95%

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14
Q

True or false

The process of standardizing converts an X value to a Z value

A

True

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15
Q

Describe a normal distribution

A

It is symmetric

The mean and median are identical

The standard deviation represents the distance from the mean to its inflection points

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16
Q

About ______ percent of normal distribution values lie within one standard deviation of the mean

A

68%

17
Q

Z distribution values are called

A

Standard scores, z- scores, and Z-values

18
Q

True or false

Does the distribution is normally distributed with a mean of zero and a standard deviation of one?

A

True

19
Q

True or false

The Z-distribution belongs to the normal distribution family and serves as the standard by which other normal distributions are evaluated

A

True

20
Q

A z-Score represents the….

A

Number of standard deviations that have value lies above or below the mean.