1. Here are the costs of 10 electric glass-top ranges rated very good or excellent by Consumer Reports in August 2013.
$765 $955 $1050 $1100 $1200 $1240 $1250 $1400 $1450 $1650
a) Find the median.
b) Find the first and third quartiles.
c) Find the IQR.
d) Find the upper and lower fences.
e) Does the set contain outliers? If so, what are they
2. The reading speed of fourth graders is normally distributed, with a mean of 92 words per minute (wpm) and a standard deviation of 8 words per minute. (Show the appropriate area by shading under thenormal curve)
a) What is the probability that a randomly selected student will read less than 88 words per minute?
b) What is the probability that a randomly selected student will read more than 116 words per minute?
c) Do you think it would unusual for a fourth grade to have a reading rate of greater than 116 wpm? Explain.
d) What reading rate would correspond to the 85th percentile?
e) A random sample of 16 fourth graders chosen. What is the probability that a random sample of 16 fourth grade students results in a mean reading rate of more than 97 wpm?
3. The distribution of actual weights of 7-ounce chocolate bars produced by a certain machine is Normal with mean 7.1 ounces and standard deviation 0.2 ounces. Company managers do not want the weight of a chocolate bar to fall below 6.95 ounces, for fear that consumers will complain.
a) Find the probability that the weight of a randomly selected candy bar is less than 6.95 ounces. Sixteen candy bars are selected at random and their mean weight, x , is computed.
b) Find the probability that the mean weight of the sixteen candy bars is less than 6.95 ounces.
4. The army reports that the distribution of head circumference among male soldiers is approximately Normal with mean 22.8 inches and standard deviation 1.1 inches. Show your method.
(a) A male soldier whose head circumference is 23.6 inches would be at what percentile?
(b) What percent of soldiers have head circumference between 20.6 inches and 24.2 inches?
(c) Would it be unusual for a randomly selected soldier to have a head circumference of 26.9 inches?