Section 3.3 Homework

1.  Suppose the first class in a frequency table of quantitative data is 0-4 and the second class is 5-9. What is the class midpoint of the first​ class? ​(This is a reading assessment question. Be certain of your answer because you only get one attempt on this​ question.)

The class midpoint of the first class is _________.

2.   The following data represent the number of people aged 25 to 64 years covered by health insurance​ (private or​ government) in 2018. Approximate the mean and standard deviation for age.

Mean =

Standard Deviation =

3.   Recently, a random sample of 13–18 year olds was​ asked, “How much do you currently have in​ savings?” The data in the table represent the responses to the survey. Approximate the mean and standard deviation amount of savings.

The sample mean amount of savings is  ______ ​(Round to the nearest dollar as​ needed.)

The sample standard deviation is ______  (Round to the nearest dollar as​ needed.)

4.  The frequency distribution was obtained using a class width of 0.5 for data on cigarette tax rates. Use the frequency distribution to approximate the population mean and population standard deviation. Compare these results to the actual mean ì=​$1.727 and standard deviation ó=​$1.088.

The population mean is ______  (Round to three decimal places as​ needed.)

The population standard deviation is  _________ ​(Round to three decimal places as​ needed.)

Compare these results to the values found using the actual data.

1. The grouped values are both slightly larger.
2. The grouped mean is slightly​ larger, while the grouped standard deviation is slightly smaller.
3. The grouped values are both slightly smaller.
4. The grouped mean is slightly​ smaller, while the grouped standard deviation is slightly larger.

5.  Jamie has just completed her second semester in college. She earned a grade of B in her 3​-hour calculus ​course, a grade of C in her 4​-hour psychology ​course, a grade of C in her 3​-hour physics ​course, and a grade of B in her 3​-hour studio art course. Assuming that A equals 4​ points, B equals 3​ points, C equals 2​ points, D equals 1​ point, and F is worth no​ points, determine Jamie​’s ​grade-point average for the semester.

Jamie​’s grade point average is ______

6.  Ester and George want to make perfume. In order to get the right balance of ingredients for their tastes they bought 3 ounces of rose oil at $3.51 per ounce, 4 ounces of ginger essence for $3.83 per ounce, and 4 ounces of black currant essence for $2.35 per ounce. Determine the cost per ounce of the perfume.

The cost per ounce of the perfume is ________  (Round to the nearest​ cent.)

7.