Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.


1.

Using
the standard normal distribution tables, what is the area under the standard normal curve
corresponding to –0.5 < Z < 1.2? a.  0.3085.
 c.  0.5764.
 b.  0.8849.
 d.  0.2815.
    


2.

The
temperature at any random location in a kiln used in the manufacture of bricks is normally
distributed with a mean of 1000 and a standard deviation of 50° F.
When glazed
bricks are put in the oven, if the temperature is below 900°F they will miscolor. If the bricks
are placed randomly throughout the kiln, the proportion of glazed bricks that miscolor is closest to
a.  49.38%.
 c.  47.72%.
 b.  2.28%.
 d.  0.62%.
    


3.

The
distribution of actual weights of 8.0ounce chocolate bars produced by a certain machine is normal
with a mean of 8.1 ounces and a standard deviation of 0.1 ounces.
The proportion
of chocolate bars weighing less than 8.0 ounces is a.  0.500.
 c.  0.341.
 b.  0.159.
 d.  0.841.
    


4.

The
distribution of actual weights of 8.0ounce chocolate bars produced by a certain machine is normal
with a mean of 8.1 ounces and a standard deviation of 0.1 ounces.
The proportion
of chocolate bars weighing between 8.2 and 8.3 ounces is a.  0.819  c.  0.477  b.  0.636  d.  0.136     


5.

Birthweights at a local hospital have a normal distribution with a mean of 110 ounces
and a standard deviation of 15 ounces. The proportion of infants with birthweights between 125 ounces
and 140 ounces is a.  0.819  c.  0.477  b.  0.636  d.  0.136     


6.

The
scores on a university examination are normally distributed with a mean of 62 and a standard
deviation of 11. If the bottom 5% of students will fail the course, what is the lowest mark that a
student can have and still be awarded a passing grade?


7.

The
time taken to prepare the envelopes to mail a weekly report to all executives in a company has a
normal distribution with a mean of 35 minutes and a standard deviation of 2 minutes. On 95% of
occasions the mailing preparation takes less than a.  38.29
minutes  c.  35.25
minutes  b.  31.71 minutes  d.  34.75 minutes     


8.

A
softdrink machine can be regulated so that it discharges an average of m ounces per cup.
If the ounces of fill are normally distributed with a standard deviation of 0.4 ounces, what value
should m be set at so
that 6ounce cups will overflow only 2% of the time?


9.

The
weights of packets of cookies produced by a certain manufacturer have a normal distribution with a
mean of 202 grams and a standard deviation of 3 grams. The weight that should be stamped on the
packet so that only 1% of packets are underweight is a.  209
grams  c.  202
grams  b.  195 grams  d.  Not enough information to tell     


10.

The
distribution of actual weights of 8ounce chocolate bars produced by a certain machine is normal with
a mean of 8.1 ounces and a standard deviation of 0.1 ounces. What weight should be put on the
chocolate bar wrappers so that only 1% of bars are underweight? a.  7.77
ounces  c.  7.87
ounces  b.  8.33 ounces  d.  8.23 ounces     


11.

Which
of the following four histograms would best be approximated by a normal distribution?


12.

The
heights of Americn men aged 18 to 24 are approximately normally distributed with mean 68 inches and
standard deviation 2.5 inches. Half of all young men are shorter than a.  65.5
inches  d.  can't tell,
because the median height is not given  b.  68 inches  e.  none of the above  c.  70.5
inches     


13.

The
heights of Americn men aged 18 to 24 are approximately normally distributed with mean 68 inches and
standard deviation 2.5 inches. Only about 5% of young men have heights outside the
range a.  65.5 inches to
70.5 inches  d.  58 inches to 78
inches  b.  63 inches to 73 inches  e.  none of the above  c.  60.5 inches to
75.5 inches     


14.

The
area under the standard normal curve corresponding to 0.3<Z<1.6 is a.  0.3273  d.  0.9542  b.  0.4713  e.  None of the above  c.  0.5631     


15.

Suppose that sixteenounce bags of chocolate chip cookies are produced with an actual
mean weight of 16.1 ounches and a standard deviaion of 0.1 ounce. The percentage of bags that
will contain between 16.0 and 16.1 ounces is a.  10  d.  68  b.  16  e.  None of the above  c.  34     


16.

Suppose that sixteenounce bags of chocolate chip cookies are produced with an actual
mean weight of 16.1 ounches and a standard deviaion of 0.1 ounce. Approximately what percentage
of bags will likely be underweight (i.e. less than 16 ounces) a.  10  d.  64  b.  16  e.  None of the above  c.  32     


17.

Which
statement is true for any density curve? a.  The bars must be of equal
widtth.  d.  One can use
Table A (table of standard normal values) to find relative frequencies.  b.  It is
symmetric.  e.  None of the
above is correct.  c.  It must either steadily rise or steadily fall, since it cannot
do both.     


18.

A
company produces packets of soap powder labeled "Giant Size 32 Ounces." The actual
weight of soap powder in a box has a normal distribution with a mean of 33 oz. and a standard
deviation of 0.8 oz. What proportion of packets are underweight (i.e. weigh less than 32
oz.)?
a.  0.159  d.  0.841  b.  0.212  e.  0.115  c.  0.106     


19.

If
the heights of 99.7% of American men are between 5'0" and 7'0", what is your estimate of
the standard deviation of the height of American men?


20.

The
average yearly snowfall in Chillyville is normally distributed with a mean of 55 inches. If the
snowfall in Chillyville exceeds 60 inches in 15% of the years, what is the standard
deviation? a.  4.83
inches  d.  8.93
inches  b.  5.18 inches  e.  The standard deviation cannot be computed from the given
information  c.  6.04 inches     
