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Descriptive Statistic - Statistics - Solved Quiz, Exercises of Statistics

This lecture is from Statistics. Key important points are: Descriptive Statistic, Dow Jones Travel Index, Business Travelers, Hotel Rooms, Median Hotel Room Rate, Mean Hotel Room Rate, Marketing Majors, Accounting Majors, Individual Investors, Survey of Discount Brokers

Typology: Exercises

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1) A numerical description of the outcome of an experiment is called a
A)descriptive statistic
B)probability function
C)variance
D)random variable
The correct answer is d
2) A random variable that can assume only a finite number of values is referred to as a(n)
A)infinite sequence
B)finite sequence
C)discrete random variable
D)discrete probability function
The correct answer is c
3) A probability distribution showing the probability of x successes in n trials, where the probability
of success does not change from trial to trial, is termed a
A)uniform probability distribution
B)binomial probability distribution
C)hypergeometric probability distribution
D)normal probability distribution
The correct answer is b
4) Variance is
A)a measure of the average, or central value of a random variable
B)a measure of the dispersion of a random variable
C)the square root of the standard deviation
D)the sum of the squared deviation of data elements from the mean
The correct answer is b
5) A continuous random variable may assume
A)any value in an interval or collection of intervals
B)only integer values in an interval or collection of intervals
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Download Descriptive Statistic - Statistics - Solved Quiz and more Exercises Statistics in PDF only on Docsity!

1) A numerical description of the outcome of an experiment is called a

A) B)descriptive statisticprobability function

C)variance

D)random variable

The correct answer is d

2) A random variable that can assume only a finite number of values is referred to as a(n)

A)infinite sequence

B)finite sequence

C) D)discrete random variablediscrete probability function

The correct answer is c

3) of success does not change from trial to trial, is termed a A probability distribution showing the probability of x successes in n trials, where the probability

A) B)uniform probability distributionbinomial probability distribution

C) D)hypergeometric probability distributionnormal probability distribution

The correct answer is b

4) Variance is

A)a measure of the average, or central value of a random variable

B)a measure of the dispersion of a random variable

C)the square root of the standard deviation

D)the sum of the squared deviation of data elements from the mean

The correct answer is b

5) A continuous random variable may assume

A) B)any value in an interval or collection of intervalsonly integer values in an interval or collection of intervals

C)only fractional values in an interval or collection of intervals

D)only the positive integer values in an interval

The correct answer is a

6) The standard deviation is the

A)variance squared

B)square root of the sum of the deviations from the mean

C) D)same as the expected valuepositive square root of the variance

The correct answer is d

7) An experiment consists of making 80 telephone calls in order to sell a particular insurance policy.

The random variable in this experiment is a

A) B)discrete random variablecontinuous random variable

C)complex random variable

D)simplex random variable

The correct answer is a

8) An experiment consists of determining the speed of automobiles on a highway by the use of radar

equipment. The random variable in this experiment is a

A) B)discrete random variablecontinuous random variable

C)complex random variable

D)simplex random variable

The correct answer is b

9) Twenty percent of the students in a class of 100 are planning to go to graduate school. The

standard deviation of this binomial distribution is

A) B) 2016

C) D) 42

E)-

The correct answer is c

14) Assume that you have a binomial experiment with p = 0.5 and a sample size of 100. The

expected value of this distribution is

A)0.

B) C)0.30 100

D) 50

E)-

The correct answer is d

15) The variance for the binomial probability distribution is

A)var(x) = P(1 - P)

B) C)var(x) = nPvar(x) = n(1 - P)

D)var(x) = nP(1 - P)

E)-

The correct answer is d

16) The random variable x is the number of occurrences of an event over an interval of ten minutes. It

can be assumed that the probability of an occurrence is the same in any two-time periods of an equallength. It is known that the mean number of occurrences in ten minutes is 5.3.

The random variable x satisfies which of the following probability distributions?

A) B)normalPoisson

C)binomial

D)Not enough information is given to answer this question.

E)-

The correct answer is b

17)can be assumed that the probability of an occurrence is the same in any two-time periods of an equal The random variable x is the number of occurrences of an event over an interval of ten minutes. It

length. It is known that the mean number of occurrences in ten minutes is 5.3.

The appropriate probability distribution for the random variable is

A)discrete

B)continuous

C)either discrete or continuous depending on how the interval is defined

D)None of these alternatives is correct.

E)-

The correct answer is a

18) The probability that a continuous random variable takes any specific value

A)is equal to zero

B) C)is at least 0.5depends on the probability density function

D)is very close to 1.

E)-

The correct answer is a

  1. Normal distribution is a skewed distribution with its tails extending to infinity on either side of the mean. A) B)TrueFalse C) D)-- E)- The correct answer is b

  2. A z-score is the number of standard deviations that a value of a random variable is above or below the mean. A)True B) C)False- D)- E)- The correct answer is a

  3. In a standard normal distribution, if the area under curve to the right of a z-value is 0.10, then the area to the left of the same z-value is -0.10.

A) B)TrueFalse C) D)-- E)-

The correct answer is c

  1. Suppose x is a normal random variable with mean 60 and standard deviation 2. A z score was calculated for a number, and the z score is 3.4. What is x?

A)63. B)56. C)68. D)53. E) 66. The correct answer is e

  1. Within a range of z scores from -1 to +1, you can expect to find _______ per cent of the values in a normal distribution.

A) 95 B) 99 C) 68 D) 34 E) 100 The correct answer is c

  1. Let x be a binomial random variable with n =20 and p =.8. If we use the normal distribution to approximate probabilities for this, a correction for continuity should be made. To find the probability of more than 12 successes, we should find _______.

A)P( x >12.5) B) P( x >12) C)P( x >11.5) D)P( x <11.5) E)P( x < 12) The correct answer is a

  1. A population list, map, directory, or other source used to represent the population from which a sample is taken is called the census. A)True B) C)False-

D)-

E)-

The correct answer is b

  1. With cluster sampling, there is homogeneity within a subgroup or stratum. A) B)TrueFalse C) D)-- E)- The correct answer is b
  2. In a random sampling technique every unit of the population has a randomly varying chance or probability of being included in the sample. A) B)TrueFalse C) D)-- E)- The correct answer is b
  3. The standard deviation of a sampling distribution of the sample means is commonly called the standard error of the mean. A) B)TrueFalse C) D)-- E)- The correct answer is a
  4. Increasing the sample size causes the numerical value of standard error of the mean to increase. A) B)TrueFalse C) D)-- E)- The correct answer is b

The correct answer is a

  1. According to the central limit theorem, if a sample of size 81 is drawn from a population with a standard deviation of 72, the standard deviation of the distribution of the sample means would equal _______.

A) 8 B) 9 C)7. D)0. E)128. The correct answer is a

  1. Increasing the sample size causes the sampling distribution of xbar to ________.

A) shift to the right B)shift to the left C)have more dispersion D) have less dispersion E) stay unchanged The correct answer is d

normal distribution is used to approximate the discrete binomial distribution is called^ 39)^ A value of 0.5 that is added and/or subtracted from a value of x when the continuous

A)50% of the area under the normal curve

B)continuity correction factor

C) D)factor of conversionall of the alternatives are correct answers

E)-

The correct answer is b

40) In a standard normal distribution, the range of values of z is from

A)minus infinity to infinity

B) C)-1 to 10 to 1

D)-3.09 to 3.

E)-

The correct answer is a

41) Larger values of the standard deviation result in a normal curve that is

A) B)shifted to the rightshifted to the left

C)narrower and more peaked

D)wider and flatter

E)-

The correct answer is d

42) A probability distribution is an equation that

A)associates a particular probability of occurrence with each outcome in the sample space.

B) C)measures outcomes and assigns values ofassigns a value to the variability in the sample space. X to the simple events.

D)assigns a value to the center of the sample space.

E)-

The correct answer is a

43) Whenever p = 0.1 and n is small, the binomial distribution will be

A)symmetric

B) C)right-skewedleft-skewed

D)None of the above

E)-

The correct answer is b

44) If the outcomes of a random variable follow a Poisson distribution, then their

A)mean equals the standard deviation.

B) C)median equals the standard deviation.mean equals the variance.

D)median equals the variance.

E)-

The correct answer is c

45) If p remains constant in a binomial distribution, an increase in n will increase the

A) B)TrueFalse C) D)-- E)- The correct answer is a

Ωηεν τηε ποπυλατιον στανδαρδ δεϖιατιον, σ, ισ υνκνοων τηε σαμπλε στανδαρδ δεϖ ιατιον,σ, ισ υσεδ ιν δετερμινινγ τηε ιντερϖαλ εστιματε φορ τηε ποπυλατιον μεαν. A) B)TrueFalse C) D)-- E)− The correct answer is a

  1. Catherine Chao, Director of Marketing Research, is evaluating consumer acceptance of a new toothpaste package. Her staff reports that 17% of a random sample of 200 households prefers the new package to all other package designs. If Catherine concludes that 17% of all households prefer the new package, she is using a _______. A) a point estimate B) a range estimate C) an interval estimate D) an exact estimate E) a statistical parameter

The correct answer is a

  1. The z value associated with a two-sided 90% confidence interval is _______.

A)1. B)1. C)1. D) 2. E)2. The correct answer is b

  1. The z value associated with a two-sided 95% confidence interval is _______. A) 1. B) C)1.6451. D)2. E)2. The correct answer is c
  2. The normal distribution is used to test about a population mean for large samples if the population standard deviation is known. "Large" is usually defined as _______.

A) at least 10 B) at least 5% of the population size C) at least 30 D) at least 12 E) at least 100 The correct answer is c

55) The absolute value of the difference between the point estimate and the population

parameter it estimates is

A) B)the standard errorthe sampling error

C)precision

D)the error of confidence

E)-

The correct answer is b

56) When s is used to estimate s, the margin of error is computed by using

A) B) normal distribution t distribution

C) the mean of the sample

D) the mean of the population

E)-

The correct answer is b

A)standard distribution

B) C)z distributionalpha distribution

D)t distribution

E)-

The correct answer is d

61) In interval estimation, the t distribution is applicable only when

A)the population has a mean of less than 30

B) C)the sample standard deviation is used to estimate the population standard deviationthe variance of the population is known

D)the standard deviation of the population is known

E)-

The correct answer is b

62) In order to use the normal distribution for interval estimation of m when s is

known and the sample is very small, the population

A) must be very large

B) must have a normal distribution

C) D) can have any distribution must have a mean of at least 1

E)-

The correct answer is b

63) From a population that is not normally distributed and whose standard deviation is not

known, a

sample of 6 items is selected to develop an interval estimate for the mean of the population (μ).

A) B)The normal distribution can be used.The t distribution with 5 degrees of freedom must be used.

C)The t distribution with 6 degrees of freedom must be used.

D)The sample size must be increased.

E)−

The correct answer is d

the standard^ 64)^ From a population that is normally distributed, a sample of 25 elements is selected and

deviation of the sample is computed. For the interval estimation of is the μ, the proper distribution to use

A)normal distribution

B)t distribution with 25 degrees of freedom

C) D)t distribution with 26 degrees of freedomt distribution with 24 degrees of freedom

E)−

The correct answer is d

65) As the sample size increases, the margin of error

A) B)IncreasesDecreases

C)stays the same

D)increases or decreases depending on the size of the mean

E)-

The correct answer is b

confidence coefficient is reduced to 0.90, the interval for m^ 66)^ A 95% confidence interval for a population mean is determined to be 100 to 120. If the

A)becomes narrower

B) C)becomes widerdoes not change

D)becomes 0.

E)-

The correct answer is a

67) After computing a confidence interval, the user believes the results are meaningless

because the width of the interval is too large. Which one of the following is the best

71) Which of the following best describes the form of the sampling distribution of the sample

proportion?

A) B)When standardized, it is exactly the standard normal distribution.When standardized, it is the t distribution.

C)It is approximately normal as long as n 30.

D)It is approximately normal as long as np 5 and n(1-p) 5.

E)−

The correct answer is d