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Statistics final exam

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study guide for statistics final exam
Jess Todd
Quiz by Jess Todd, updated more than 1 year ago
Jess Todd
Created by Jess Todd over 9 years ago
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Question 1

Question
which of the following are binomial experiments or can be reduced to binomial experiments?
Answer
  • surveying 100 people to determine if they like sudsy soap
  • tossing a coin 100 times to see how many heads occur
  • drawing a card with replacement from a deck and getting a heart
  • asking 1000 people which brand of cigarettes
  • testing four different brands of aspirin to see which brands are effective

Question 2

Question
the expected value of a random variable can be thought of as a long-run average
Answer
  • True
  • False

Question 3

Question
the number of courses a student is taking this semester is an example of a continuous random variable
Answer
  • True
  • False

Question 4

Question
when the binomial distribution is used, the outcomes must be dependent
Answer
  • True
  • False

Question 5

Question
a binomial experiment has a fixed number of trials
Answer
  • True
  • False

Question 6

Question
what is the sum of the probabilities of all outcomes in a probability distribution
Answer
  • 0
  • 1/2
  • 1
  • it cannot be determined

Question 7

Question
how many outcomes are there in a binomial experiment
Answer
  • 0
  • 1
  • 2
  • it varies

Question 8

Question
the number of trials for a binomial experiment
Answer
  • can be infinite
  • is unchanged
  • is unlimited
  • must be fixed

Question 9

Question
the total area under a normal distribution is infinite
Answer
  • True
  • False

Question 10

Question
the standard normal distribution is a continuous distribution
Answer
  • True
  • False

Question 11

Question
all variables that are approximately normally distributed can be transformed to standard normal variables
Answer
  • True
  • False

Question 12

Question
the z value corresponding to a number below the mean is always negative
Answer
  • True
  • False

Question 13

Question
the area under the standard normal distribution to the left of z=0 is negative
Answer
  • True
  • False

Question 14

Question
the central limit theorem applies to means of samples selected from different populations
Answer
  • True
  • False

Question 15

Question
the mean of the standard normal distribution is
Answer
  • 0
  • 1
  • 100
  • variable

Question 16

Question
approximately what percentage of normally distributed data values will fall within 1 standard deviation above or below the mean?
Answer
  • 68%
  • 95%
  • 99.7%
  • variable

Question 17

Question
which is not a property of the standard normal distribution?
Answer
  • it's symmetric about the mean
  • it's uniform
  • it's bell shaped
  • its unimodal

Question 18

Question
when a distribution is positively skewed, the relationship of the mean, median, and mode from left to right will be?
Answer
  • mean, median, mode
  • mode, median, mean
  • median, mode, mean
  • mean, mode, median

Question 19

Question
the standard deviation of all possible sample means equals
Answer
  • the population standard deviation
  • the population standard deviation divided by the population mean
  • the population standard deviation divided by the square root of the sample size
  • the square root of the population standard deviation

Question 20

Question
Interval estimates are preferred over point estimates since the confidence level can be specified
Answer
  • True
  • False

Question 21

Question
for a specific confidence interval, the larger the sample size, the smaller the margin of error will be.
Answer
  • True
  • False

Question 22

Question
an estimator is consistent if as the sample size decreases, the value of the estimator approaches the value of the parameter estimated
Answer
  • True
  • False

Question 23

Question
to determine the sample size needed to estimate a parameter, you must know the margin of error
Answer
  • True
  • False

Question 24

Question
when a 99% confidence interval is calculated instead of a 95% confidence interval with n being the same, the margin of error will be
Answer
  • smaller
  • larger
  • the same
  • it cannot be determined

Question 25

Question
the best point of estimate of the population mean is
Answer
  • the sample mean
  • the sample median
  • the sample mode
  • the sample midrange

Question 26

Question
when the population standard deviation is unknown and the sample size is less than 30, what table value should be used in computing a confidence interval for a mean
Answer
  • z
  • t
  • chi-square
  • none of the above

Question 27

Question
No error is committed when the null hypothesis is rejected when it is false
Answer
  • True
  • False

Question 28

Question
when you are conducting the t test, the population must be approximately normally distributed
Answer
  • True
  • False

Question 29

Question
the test value separates the critical region from the noncritical region
Answer
  • True
  • False

Question 30

Question
the values of chi-square test cannot be negative
Answer
  • True
  • False

Question 31

Question
the chi-square test for variance is always one tailed
Answer
  • True
  • False

Question 32

Question
when the value of alpha is increased, the probability of committing a type 1 error is
Answer
  • decreased
  • increased
  • the same
  • none of the above

Question 33

Question
if you wish to test the claim that the mean of the population is 100, the appropriate null hypothesis is
Answer
  • x(bar) = 100
  • µ ≥ 100
  • µ ≤ 100
  • µ = 100

Question 34

Question
the degrees of freedom for the chi-square test for variances or standard deviation are
Answer
  • 1
  • n
  • n - 1
  • none of the above

Question 35

Question
for the t test, one uses ________ instead of σ
Answer
  • n
  • s
  • X²
  • t

Question 36

Question
a negative relationship between two variables means that for the most part, as the x variable increases, the y variable decreases
Answer
  • True
  • False

Question 37

Question
a correlation coefficient of -1 implies a perfect linear relationship between the variables
Answer
  • True
  • False

Question 38

Question
even if the correlation coefficient is high (near +1) or low (near -1), it may not be significant
Answer
  • True
  • False

Question 39

Question
when the correlation coefficient is significant, you can assume x causes y
Answer
  • True
  • False

Question 40

Question
it is not possible to have a significant correlation by chance alone
Answer
  • True
  • False

Question 41

Question
in multiple regression, there are several dependent variables and one independent variable
Answer
  • True
  • False

Question 42

Question
the strength of the linear relationship between two quantitative variables is determined by the value of
Answer
  • r
  • a
  • x
  • s (subscript "est")

Question 43

Question
to test the significance of r, a(n) ____ test is used.
Answer
  • t
  • F
  • X²
  • none of the above

Question 44

Question
the test of significance for r has _______ degrees of freedom.
Answer
  • 1
  • n
  • n - 1
  • n - 2

Question 45

Question
the equation of the regression line used in statistics is
Answer
  • x = a + by
  • y = bx + a
  • y' = a +bx
  • x = ay + b

Question 46

Question
the coefficient of determination is
Answer
  • r
  • r²
  • a
  • b
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