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Statistics final exam

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study guide for statistics final exam
Jess Todd
Quiz por Jess Todd, atualizado more than 1 year ago
Jess Todd
Criado por Jess Todd mais de 9 anos atrás
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Resumo de Recurso

Questão 1

Questão
which of the following are binomial experiments or can be reduced to binomial experiments?
Responda
  • 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

Questão 2

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

Questão 3

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

Questão 4

Questão
when the binomial distribution is used, the outcomes must be dependent
Responda
  • True
  • False

Questão 5

Questão
a binomial experiment has a fixed number of trials
Responda
  • True
  • False

Questão 6

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

Questão 7

Questão
how many outcomes are there in a binomial experiment
Responda
  • 0
  • 1
  • 2
  • it varies

Questão 8

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

Questão 9

Questão
the total area under a normal distribution is infinite
Responda
  • True
  • False

Questão 10

Questão
the standard normal distribution is a continuous distribution
Responda
  • True
  • False

Questão 11

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

Questão 12

Questão
the z value corresponding to a number below the mean is always negative
Responda
  • True
  • False

Questão 13

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

Questão 14

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

Questão 15

Questão
the mean of the standard normal distribution is
Responda
  • 0
  • 1
  • 100
  • variable

Questão 16

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

Questão 17

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

Questão 18

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

Questão 19

Questão
the standard deviation of all possible sample means equals
Responda
  • 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

Questão 20

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

Questão 21

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

Questão 22

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

Questão 23

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

Questão 24

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

Questão 25

Questão
the best point of estimate of the population mean is
Responda
  • the sample mean
  • the sample median
  • the sample mode
  • the sample midrange

Questão 26

Questão
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
Responda
  • z
  • t
  • chi-square
  • none of the above

Questão 27

Questão
No error is committed when the null hypothesis is rejected when it is false
Responda
  • True
  • False

Questão 28

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

Questão 29

Questão
the test value separates the critical region from the noncritical region
Responda
  • True
  • False

Questão 30

Questão
the values of chi-square test cannot be negative
Responda
  • True
  • False

Questão 31

Questão
the chi-square test for variance is always one tailed
Responda
  • True
  • False

Questão 32

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

Questão 33

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

Questão 34

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

Questão 35

Questão
for the t test, one uses ________ instead of σ
Responda
  • n
  • s
  • X²
  • t

Questão 36

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

Questão 37

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

Questão 38

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

Questão 39

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

Questão 40

Questão
it is not possible to have a significant correlation by chance alone
Responda
  • True
  • False

Questão 41

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

Questão 42

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

Questão 43

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

Questão 44

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

Questão 45

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

Questão 46

Questão
the coefficient of determination is
Responda
  • r
  • r²
  • a
  • b

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