Exam 10: Introduction to Statistics

Construct the specified histogram. -In a survey, 20 voters were asked their age. The results are summarized in the frequency table below. Construct a histogram corresponding to the frequency table.

Construct a frequency polygon. -

Find the area under the normal curve. -Find the percent of the area under a normal curve between the mean and 0.83 deviations from the mean.

Solve the problem. -Find the percent of the area under the standard normal curve between $\mathrm{z}=0.54$ and $\mathrm{z}=1.91$ .

Solve the problem. -The stem and leaf plot depicts the average weight (in pounds) of all four year olds receiving their annual influenza vaccine from the local health clinic. Describe the shape of the distribution.

Calculate the weighted average. -Rafi enrolled in a class where attendance counted as $15 \%$ of the final grade, quizzes counted as $20 \%$ , one midterm exam counted as $35 \%$ , and the final exam counted as $30 \%$ . Rafi earned $95 \%$ on attendance, $87 \%$ on the quizzes, and $86 \%$ on the midterm exam. If $90 \%$ is needed to earn a grade of $\mathrm{A}_{-}$ , what is the minimum score Rafi needs to earn on the final exam in order to earn a final grade of $\mathrm{A}-$ ? Round to the nearest hundredth.

Calculate the weighted average. -Annie enrolled in a class where the homework counts as $30 \%$ of the final grade, two midterm exams count as $10 \%$ each, and a final exam counts as $50 \%$ of the final grade. Annie earned $95 \%$ on the homework, $86 \%$ and $83 \%$ on the two midterm exams, and $87 \%$ on the final exam. What is Annie's final average? If necessary, round to the nearest hundredth.

Find a $z$ score satisfying the given condition. - $30.2 \%$ of the total area is to the left of $z$ .

In a certain distribution, the mean is 50 with a standard deviation of 6 . Use Chebyshev's theorem to tell the probabilitythat a number lies in the following interval. Round your results to the nearest whole percent. -Less than 20 or more than 80

Find the standard deviation of the data summarized in the given frequency table. -A company had 80 employees whose salaries are summarized in the frequency table below. Find the standard deviation.

Find the area under the normal curve. -Find the percent of the area under a normal curve between the mean and 1.64 deviations from the mean.

At one high school, students can run the 100-yard dash in an average of 15.2 seconds with a standard deviation of .9 seconds. The times are very closely approximated by a normal curve. Find the percent of times that are indicated. Round to the nearest whole percent. -Less than 17 seconds

Construct a boxplot. -The ages of the 21 members of a track and field team are listed below. Construct a boxplot for the data. 15 18 18 19 22 23 24 24 24 24 25 26 26 27 28 28 30 32 33 40 42

Construct a-stem and leaf display for the given data table. - 56 72 40 42 62 37 31 42 63 81 38 36 48 67 83 44 73 58 56 51

Describe the shape of the given histogram. -

Construct a boxplot. -The normal monthly precipitation (in inches) for August is listed for 20 different U.S. cities. Construct a boxplot for the data set. 0.4 1.0 1.5 1.6 2.0 2.2 2.4 2.7 3.4 3.4 3.5 3.6 3.6 3.7 3.7 3.9 4.1 4.2 4.2 7.0

Assume the distribution is normal. Use the area of the normal curve to answer the question. Round to the nearest whole percent. -A certain grade egg must weigh at least $2.5 \mathrm{oz}$ . If the average weight of an egg is $1.5 \mathrm{oz}$ , with a standard deviation of $.4 \mathrm{oz}$ , how many eggs in a sample of 9 dozen would you expect to be over the 2.5 oz size?

Assume the distribution is normal. Use the area of the normal curve to answer the question. Round to the nearest whole percent. -The average size of the fish in a lake is 11.4 inches, with a standard deviation of 3.2 inches. Find the probability of catching a fish longer than 17 inches.

Find a $z$ score satisfying the given condition. - $4 \%$ of the total area is to the right of $\mathrm{z}$ .

Obtain the five number summary for the given data. -The weights (in pounds) of 18 randomly selected adults are given below. 120 144 187 154 119 136 127 143 179 164 182 202 114 173 133 152 169 173