Unit 4- Statistics HW 7C and 7D Due Wednesday– 30 points Section 7C- Grouped Quantitative Discrete Data

Grouped Quantitative Discrete Data O You can group data values if there are many different data values with low frequencies. O Grouping data  class intervals O You still have a modal class, which means what?? O Compare these two Tables: O Data values:Frequency Table O Vs Number of cars TallyFrequencyRelative frequency—how do we calculate it? 0 to to to to to to 591 Total30

Column graph for grouped data is the same O Just have the intervals on the x-axis O Most likely you will have grouped intervals for your data. O How would you group GPA? O How would you group ages of students at GWHS

Stem and Leaf Plots O Stem and Leaf plots is a method of writing data in groups without losing information about the actual data value O For numbers with 2 digits O The first digit is the STEM O The second digit is the LEAF O So, in the number 27, 2 is the stem and 7 is the leaf O Examples:

Back to Back Stem and Leaf Plots O A back to back stem and leaf plots allows us to compare sets which are related. O The example is times for the 100 meter freestyle recorded by members of a swimming team O Name two descriptions of the data

Done with Exercise 7C, now it’s your turn to complete a question One partner should complete the Zinc half of a stem and leaf, and the other partner should complete the Lead part

Answers to example 7C

This is how I feel

Section 7D- Quantitative CONTINUOUS Data O When we measure data that is continuous, we cannot write down an exact value. Instead we write down an approximation which is only as accurate as the measuring device. O Quantitative Continuous Data is measured using a FREQUENCY HISTOGRAM or just a HISTOGRAM O There are no gaps between the columns O And the modal class is the ______ bar O **** to choose intervals, us the squareroot of the number of data points. For large data sets, we use more classes than less****

Done with Exercise 7D, now it’s your turn to complete a question

Answers to Example 7D

Section 7E- Measuring the Centre of Data O Mean- average O Mean for entire population is μ mu O Mean for sample population is Ë “x bar” O Median- middle value, or average of the two middle values O Mode- value that occurs the MOST, there can be two modes O The calculator will find the mean and median for you O Examples of mean O The average height of adult females is 5 feet 5 inches O The average height of adult females in this class is 5 feet 3 inches O which is the mean for the entire population? O Which is the mean for the sample population?

Find the mean, median, and mode

Answers O Mean = sum of all data/ number of data = 127/18 =7.06 O Median= middle data = 7 O Mode = most frequent data value =there are 5 “5’s” There are three “8’s” There are three “10’s” So, the mode is 5

Find the mean, median, and mode using a calculator Step 1: put data into the calculator -Stat -Enter, Edit -Clear L1 by highlighting L1 and hitting CLEAR and ENTER -Done, so 2 nd Quit Step 2: have the calculator find the mean and median for you -Stat - Go right, Calc -Enter, for 1-variable Stat -Enter

Done with Exercise 7E- Now it’s your turn to do an Example

Answers to Example 7E

Effects of Outliers… central tendency means mean, median, mode