Common Core Math I Unit 1 Review Day One-Variable Statistics

Warm-Up Job Number of people having the job Annual Salary President1200,000 Vice President150,000 Supervisor225,000 Sales Representative421,000 Warehouse Worker215,000 Custodian215,000 Clerical Worker312,000 1.Find the mean 2.Find the median 3.Identify any outliers 4.Which is a better representation of the center?

Homework Check 1.7

8. Describe the data in context. Why do you think the data is skewed? The distribution of medals won at the 1984 Winter Olympics in Sarajevo, Yugoslavia, is skewed to the right with a median of 4 medals and an IQR of 7 medals. This means that the middle 50% of countries won between 2 and 8 medals. Two countries, East Germany and USSR, were outliers with 24 and 25 medals each, respectively. The data is skewed to the right because of the two high outliers. Typically at the Olympics, most countries win a small number of medals and a few countries win a large number of medals, making the distribution skewed to the right.

HW 1.8

Write a few sentences comparing the two types of automobiles, based on the shape, center, spread, and any outliers of each data distribution. The distribution of miles per gallon for cars is skewed t the right. Most cars have between 25 and 30 mpg in the city, with a few cars with as many as 40 mpg. The distribution of miles per gallon for SUVs is fairly symmetrical. In general, SUVs get fewer miles per gallon than cars. The mean for cars is 32.9 mpg in the city and for SUVs is only 16.6 mpg. There is more variability in miles per gallon for cars than for SUVs. Most SUVs are within 4 mpg of the average, whereas most cars are within 7 mpg of the average.

Data descriptions Shape: Symmetrical, Skewed left, skewed right, or uniform Outliers: Use the 1.5IQR rule to identify Center: If data has outliers: use median If data does not have outliers: use mean Spread: Address Standard Deviation, Range, Interquartile Range

Measures of Center Mean: add up all data values and divide the sum by the number of data values – use if no outliers! Median: Put the numbers in order from least to greatest. Find the middle data. -- use if you have outliers Number of data values: Odd: one value Even: add the two center values and divide by 2

5 Number Summary Min: lowest data value Q1: Median of lower half Median: Middle data value Q3: Median of upper half Max: highest data value

IQR *the box in a boxplot* IQR: Q3-Q1

Outliers 1. Calculate the IQR (Range of IQR “Q3-Q1”) 2. Multiply the IQR by Add this number to Q3. 4. Any value above this amount is considered an outlier. 5. Then subtract that number from Q1. 6. Any value below this amount is an outlier.

Measure of Spread Range: Highest value – Lowest Value Standard Deviation: USE YOUR CALCULATOR!! Stat, Edit (enter data values), Stat, over to calc, enter, 2 nd 1 (for L1) Enter.

Be able to create 1.Frequency Table 2.Dotplot 3.Histogram 4.Boxplot

Homework: 2.8