BUAL 2 exam 1 questions with verified
answers graded A+ updated
It is appropriate to use the uniform distribution to describe a continuous random variable x
when
A. the area under the probability curve = 1
B. the probability curve f(x) > 0
C. the shape of the histogram of all possible values of x is nonsymmetrical
D. relative frequencies of all possible values of x are about the same. - correct answer ✔✔D.
relative frequencies of all possible values of x are about the same.
The normal approximation of the binomial distribution is appropriate when
A. np ≥ 5.
B. n(1 − p) ≥ 5.
C. np ≤ 5.n(1 − p) ≤ 5 and np ≤ 5.
D. np ≥ 5 and n(1 − p) ≥ 5. - correct answer ✔✔D. np ≥ 5 and n(1 − p) ≥ 5.
The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910
grams and a standard deviation of 5 grams. We calculated the value of z for a specific box of this
brand of cereal, and the z value was negative. This negative z value indicates that
A. we made a mistake in our calculations, as z must always be a nonnegative number.
B. the fill weight is more than 910 grams.
C. the fill weight is less than 910 grams
D. the fill weight is equal to 910 grams.
E. the fill weight may be more or less than 910 grams depending on the value of the standard
deviation. - correct answer ✔✔C. the fill weight is less than 910 grams
,Which of the following statements is not a property of the normal probability distribution?
A. The normal distribution is symmetric.
B. 95.44 percent of all possible observed values of the random variable x are within plus or
minus three standard deviations of the population mean.
C. The mean, median, and mode are equal.
D. The area under the normal curve to the right of the mean is equal to the area under the
normal curve to the left of the mean.
E. All of these answers are properties of the normal distribution. - correct answer ✔✔B. 95.44
percent of all possible observed values of the random variable x are within plus or minus three
standard deviations of the population mean.
If the random variable x is normally distributed, ______ percent of all possible observed values
of x will be within three standard deviations of the mean.
68.26
95.44
99.73
100 - correct answer ✔✔99.73
The z value tells us the number of ________ that a value of x is from the mean.
A. variances
B. standard deviations
C. medians
D. standard means - correct answer ✔✔B. standard deviations
A continuous probability distribution having a rectangular shape, where the probability is evenly
distributed over an interval of numbers is a(n) ________ distribution.
A. exponential
, B. binomial
C. normal
D. uniform - correct answer ✔✔D. uniform
The specific shape of each normal distribution is determined by its ________ and ________.
A. mean, standard deviation.
B. median, standard deviation
C. mean, variance
D. median, variance - correct answer ✔✔A. mean, standard deviation.
The area under the curve of a valid continuous probability distribution must ________.
A. equal 1
B. be between 0 and 1
C. be infinite
D. be less than 1 - correct answer ✔✔A. equal 1
________ values of the standard deviation result in a normal curve that is wider and flatter.
A. Smaller
B. Equal
C. Larger
D. Uniform - correct answer ✔✔C. Larger
The mean of a standard normal distribution is always equal to ________.
A. 1
B. .5
C. 0
answers graded A+ updated
It is appropriate to use the uniform distribution to describe a continuous random variable x
when
A. the area under the probability curve = 1
B. the probability curve f(x) > 0
C. the shape of the histogram of all possible values of x is nonsymmetrical
D. relative frequencies of all possible values of x are about the same. - correct answer ✔✔D.
relative frequencies of all possible values of x are about the same.
The normal approximation of the binomial distribution is appropriate when
A. np ≥ 5.
B. n(1 − p) ≥ 5.
C. np ≤ 5.n(1 − p) ≤ 5 and np ≤ 5.
D. np ≥ 5 and n(1 − p) ≥ 5. - correct answer ✔✔D. np ≥ 5 and n(1 − p) ≥ 5.
The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910
grams and a standard deviation of 5 grams. We calculated the value of z for a specific box of this
brand of cereal, and the z value was negative. This negative z value indicates that
A. we made a mistake in our calculations, as z must always be a nonnegative number.
B. the fill weight is more than 910 grams.
C. the fill weight is less than 910 grams
D. the fill weight is equal to 910 grams.
E. the fill weight may be more or less than 910 grams depending on the value of the standard
deviation. - correct answer ✔✔C. the fill weight is less than 910 grams
,Which of the following statements is not a property of the normal probability distribution?
A. The normal distribution is symmetric.
B. 95.44 percent of all possible observed values of the random variable x are within plus or
minus three standard deviations of the population mean.
C. The mean, median, and mode are equal.
D. The area under the normal curve to the right of the mean is equal to the area under the
normal curve to the left of the mean.
E. All of these answers are properties of the normal distribution. - correct answer ✔✔B. 95.44
percent of all possible observed values of the random variable x are within plus or minus three
standard deviations of the population mean.
If the random variable x is normally distributed, ______ percent of all possible observed values
of x will be within three standard deviations of the mean.
68.26
95.44
99.73
100 - correct answer ✔✔99.73
The z value tells us the number of ________ that a value of x is from the mean.
A. variances
B. standard deviations
C. medians
D. standard means - correct answer ✔✔B. standard deviations
A continuous probability distribution having a rectangular shape, where the probability is evenly
distributed over an interval of numbers is a(n) ________ distribution.
A. exponential
, B. binomial
C. normal
D. uniform - correct answer ✔✔D. uniform
The specific shape of each normal distribution is determined by its ________ and ________.
A. mean, standard deviation.
B. median, standard deviation
C. mean, variance
D. median, variance - correct answer ✔✔A. mean, standard deviation.
The area under the curve of a valid continuous probability distribution must ________.
A. equal 1
B. be between 0 and 1
C. be infinite
D. be less than 1 - correct answer ✔✔A. equal 1
________ values of the standard deviation result in a normal curve that is wider and flatter.
A. Smaller
B. Equal
C. Larger
D. Uniform - correct answer ✔✔C. Larger
The mean of a standard normal distribution is always equal to ________.
A. 1
B. .5
C. 0
