Question 1

In a normal distribution with   
 and SX = 10, the middle 50% of the cases fall between what scores (rounded)?

Accepted Answer

A)  41 and 59 
B)  43 and 57 
C)  38 and 62 
D)  45 and 55 
A)  41 and 59 
B)  43 and 57 
C)  38 and 62 
D)  45 and 55 B

Question 2

The frequency distribution of lifetimes of a tiny battery to power hand calculators is normal with 
   
and 
   
. Out of every 1000 batteries produced, how many would we expect to last:
(a)over 600 hours?
(b)less than 550 hours?
(c)between 500 and 550 hours?
(d)between 550 and 600 hours?
(e)over 650 hours?

Accepted Answer

(a)12
(b)841
(c)440
(d)146 or 147
(e)less than 1 (.2).

Question 3

In a normal distribution with   
 and SX = 10, what proportion of cases fall above a score of 42?

Accepted Answer

A)  .7881 
B)  .2119 
C)  .2881 
D)  .7119 
A)  .7881 
B)  .2119 
C)  .2881 
D)  .7119 A

Question 4

In a normal distribution with   
 and SX = 10, what proportion of cases fall between 45 and 55?

Accepted Answer

A)  .3085 
B)  .3830 
C)  .6170 
D)  .1915 
A)  .3085 
B)  .3830 
C)  .6170 
D)  .1915

Question 5

In a normal distribution of 400 scores with   
 and SX = 10, how many fall below 35?

Accepted Answer

A)  71 
B)  27 
C)  37 
D)  47 
A)  71 
B)  27 
C)  37 
D)  47

Question 6

Four-thousand entering freshmen at Downtown University take a mathematics proficiency test. The mean of the test is 60 with a standard deviation of 10; scores are normally distributed.
(a) The university has decided to place students who earned a score of 72 or better into honors math. How many students will be placed in honors math?
(b) The university has decided to place the bottom 30% into remedial math. What score must be earned to avoid being placed into remedial math?
(c) How many students earned a score between 45 and 55?

Accepted Answer

(a) 
 @#IMG-DLM& 
students.
(b

Question 7

In a normal distribution of 200 cases, the bottom 40 cases fall below what z score?

Accepted Answer

A)  -.25 
B)  -.84 
C)  -.52 
D)  -.37 
A)  -.25 
B)  -.84 
C)  -.52 
D)  -.37

Question 8

The proportion of cases in a normal distribution falling between   
 and 
   
is approximately

Accepted Answer

A)  .25 
B)  .50 
C)  .67 
D)  1.34 
A)  .25 
B)  .50 
C)  .67 
D)  1.34

Question 9

The normal curve is

Accepted Answer

A)  a mathematical abstraction having a particular defining equation 
B)  a law of nature 
C)  both (a) and (b) 
D)  none of the above 
A)  a mathematical abstraction having a particular defining equation 
B)  a law of nature 
C)  both (a) and (b) 
D)  none of the above

Question 10

In a normal distribution of 200 cases, what z score divides the top 20 cases from the bottom 180?

Accepted Answer

A)  +1.28 
B)  +.25 
C)  +.84 
D)  +1.96 
A)  +1.28 
B)  +.25 
C)  +.84 
D)  +1.96

Question 11

Which of the following characteristics is the same for all normal curves?

Accepted Answer

A)  their means 
B)  their standard deviations 
C)  their slope 
D)  all of the above 
A)  their means 
B)  their standard deviations 
C)  their slope 
D)  all of the above

Question 12

Which, if any, is not a property of the normal curve?

Accepted Answer

A)  it is continuous 
B)  its mean and median differ only slightly 
C)  its mean may take various values 
D)  its standard deviation may take various values 
A)  it is continuous 
B)  its mean and median differ only slightly 
C)  its mean may take various values 
D)  its standard deviation may take various values

Question 13

In a normal distribution, what proportion of cases falls below

Accepted Answer

A)  .4192 
B)  .0808 
C)  .9192 
D)  .5808 
A)  .4192 
B)  .0808 
C)  .9192 
D)  .5808

Question 14

In a normal distribution, the bottom 75% of the cases fall below what z score?

Accepted Answer

A)  +.50 
B)  +.38 
C)  +1.28 
D)  +.67 
A)  +.50 
B)  +.38 
C)  +1.28 
D)  +.67

Question 15

In a normal distribution of employment screening test scores with a mean of 95 and a standard deviation of 25, what is (are) the score(s):
(a) above which the top 5% of the cases fall?
(b) below which the bottom 52% of the cases fall?
(c) below which the bottom 88% of the cases fall?
(d) below which the bottom 10% of the cases fall?
(e) between which the central 30% of the cases lie?

Accepted Answer

(a) 136 
(b) 96 
(c)

Question 16

The gasoline mileages for city driving obtained by drivers of a certain brand of compact car are normally distributed with 
   
 m.p.g. and SX = 2.3 m.p.g. What proportion of drivers obtain:
(a)less than 23 m.p.g.?
(b)less than 30 m.p.g.?
(c)between 25 and 30 m.p.g.?
(d)between 28 and 32 m.p.g.?

Accepted Answer

(a).0375
(

Question 17

In a normal distribution of 200 cases, how many fall above

Accepted Answer

A)  39 
B)  79 
C)  21 
D)  11 
A)  39 
B)  79 
C)  21 
D)  11

Question 18

In a normal distribution, the middle 20% of the cases fall between what two z scores?

Accepted Answer

A)  -.52 and +.52 
B)  -.84 and +.84 
C)  -1.28 and +1.28 
D)  -.25 and +.25 
A)  -.52 and +.52 
B)  -.84 and +.84 
C)  -1.28 and +1.28 
D)  -.25 and +.25

Question 19

All normal curves

Accepted Answer

A)  are unimodal 
B)  are symmetrical 
C)  are asymptotic to the horizontal axis 
D)  have all of the above properties 
A)  are unimodal 
B)  are symmetrical 
C)  are asymptotic to the horizontal axis 
D)  have all of the above properties

Question 20

For a sample of 200 laboratory rats, the mean time to traverse a special experimental maze on the first trial was 22.5 seconds with a standard deviation of 4.7 seconds. Use the normal curve model to estimate the value(s):
(a)below which the 20 shortest time scores fell;
(b)above which the 50 longest time scores fell;
(c)below which the 130 shortest time scores fell;
(d)between which the central 140 time scores fell

Accepted Answer

(a) 16.5
(

In a normal distribution with and S_X = 10, the middle 50% of the cases fall between what scores (rounded)?

The frequency distribution of lifetimes of a tiny battery to power hand calculators is normal with and . Out of every 1000 batteries produced, how many would we expect to last: (a)over 600 hours? (b)less than 550 hours? (c)between 500 and 550 hours? (d)between 550 and 600 hours? (e)over 650 hours?

In a normal distribution with and S_X = 10, what proportion of cases fall above a score of 42?

In a normal distribution with and S_X = 10, what proportion of cases fall between 45 and 55?

In a normal distribution of 400 scores with and S_X = 10, how many fall below 35?

In a normal distribution of 200 cases, the bottom 40 cases fall below what z score?

The proportion of cases in a normal distribution falling between and is approximately

The normal curve is

In a normal distribution of 200 cases, what z score divides the top 20 cases from the bottom 180?

Which of the following characteristics is the same for all normal curves?

Which, if any, is not a property of the normal curve?

In a normal distribution, what proportion of cases falls below

In a normal distribution, the bottom 75% of the cases fall below what z score?

The gasoline mileages for city driving obtained by drivers of a certain brand of compact car are normally distributed with m.p.g. and S_X= 2.3 m.p.g. What proportion of drivers obtain: (a)less than 23 m.p.g.? (b)less than 30 m.p.g.? (c)between 25 and 30 m.p.g.? (d)between 28 and 32 m.p.g.?

In a normal distribution of 200 cases, how many fall above

In a normal distribution, the middle 20% of the cases fall between what two z scores?

All normal curves

Introduction

Frequency Distributions, Percentiles,

Graphic Representation of Frequency Distributions

Central Tendency

Variability and Standard Z Scores

Correlation

Prediction

Interpretive Aspects of Correlation and Regression

Probability

Random Sampling and Sampling Distributions

Introduction to Statistical Inference: Testing Hypotheses About Single Means Z and T

Interpreting the Results of Hypothesis Testing: Effect Size, Type I and Type II Errors, and Power

Testing Hypotheses About the Difference Between Two Independent Groups

Testing for a Difference

Inference About Correlation Coefficients

An Alternative to Hypothesis Testing: Confidence Intervals

Testing for Differences Among Three or More Groups: One-Way Analysis of Variance and Some Alternatives

Factorial Analysis of Variance

Chi-Square and Inference About Frequencies

Some Almost Assumption-Free Tests

Filters

Exam 6: Standard Scores and the Normal Curve

In a normal distribution with and SX = 10, the middle 50% of the cases fall between what scores (rounded)?

The frequency distribution of lifetimes of a tiny battery to power hand calculators is normal with and . Out of every 1000 batteries produced, how many would we expect to last: (a)over 600 hours? (b)less than 550 hours? (c)between 500 and 550 hours? (d)between 550 and 600 hours? (e)over 650 hours?

In a normal distribution with and SX = 10, what proportion of cases fall above a score of 42?

In a normal distribution with and SX = 10, what proportion of cases fall between 45 and 55?

In a normal distribution of 400 scores with and SX = 10, how many fall below 35?

In a normal distribution of 200 cases, the bottom 40 cases fall below what z score?

The proportion of cases in a normal distribution falling between and is approximately

The normal curve is

In a normal distribution of 200 cases, what z score divides the top 20 cases from the bottom 180?

Which of the following characteristics is the same for all normal curves?

Which, if any, is not a property of the normal curve?

In a normal distribution, what proportion of cases falls below

In a normal distribution, the bottom 75% of the cases fall below what z score?

The gasoline mileages for city driving obtained by drivers of a certain brand of compact car are normally distributed with m.p.g. and SX = 2.3 m.p.g. What proportion of drivers obtain: (a)less than 23 m.p.g.? (b)less than 30 m.p.g.? (c)between 25 and 30 m.p.g.? (d)between 28 and 32 m.p.g.?

In a normal distribution of 200 cases, how many fall above

In a normal distribution, the middle 20% of the cases fall between what two z scores?

All normal curves

Introduction

Frequency Distributions, Percentiles,

Graphic Representation of Frequency Distributions

Central Tendency

Variability and Standard Z Scores

Correlation

Prediction

Interpretive Aspects of Correlation and Regression

Probability

Random Sampling and Sampling Distributions

Introduction to Statistical Inference: Testing Hypotheses About Single Means Z and T

Interpreting the Results of Hypothesis Testing: Effect Size, Type I and Type II Errors, and Power

Testing Hypotheses About the Difference Between Two Independent Groups

Testing for a Difference

Inference About Correlation Coefficients

An Alternative to Hypothesis Testing: Confidence Intervals

Testing for Differences Among Three or More Groups: One-Way Analysis of Variance and Some Alternatives

Factorial Analysis of Variance

Chi-Square and Inference About Frequencies

Some Almost Assumption-Free Tests

Filters

In a normal distribution with and S_X = 10, the middle 50% of the cases fall between what scores (rounded)?

In a normal distribution with and S_X = 10, what proportion of cases fall above a score of 42?

In a normal distribution with and S_X = 10, what proportion of cases fall between 45 and 55?

In a normal distribution of 400 scores with and S_X = 10, how many fall below 35?

The gasoline mileages for city driving obtained by drivers of a certain brand of compact car are normally distributed with m.p.g. and S_X= 2.3 m.p.g. What proportion of drivers obtain: (a)less than 23 m.p.g.? (b)less than 30 m.p.g.? (c)between 25 and 30 m.p.g.? (d)between 28 and 32 m.p.g.?