Comparative Inferences

Valid inferences are based on data and are most likely true.

A ___ is the entire group of objects or individuals being studied.

A ___ is a part of a group being surveyed.

In order to collect good data, the sample needs to be unbiased.

To have an unbiased sample, it should be ___ and ___.

Select two answer choices.

Several students were surveyed about their favorite drinks.

22 Fanta, 34 Pepsi, 20 Coke, and 29 Grape.

Predict how many students will like Coke if 500 students are surveyed?

Bob asked 8 band members and found that 3 members play more than one instrument.

Use his results to predict how many of Oak School's 152 band members play more than one instrument.

The TV station wants to get the opinion of viewers on the look of a new game-show set.  

The station's staff calls random people in the phone book.  Is this biased or unbiased?

The mean is found by ___ all of the numbers and then ___ by the number of items.

Find the mean of these numbers.
5, 11, 2, 12, 4, 2

Lizzy had test scores of 72, 94, 108, 60.
What is the range of her test scores?

When finding the median, what do you do if there are two numbers in the middle of the set of data?

Find the median of the set of numbers.

60, 58, 52, 48, 60, 67

Find the median.

Find the median.

3, 5, 7, 4, 3, 1

What are two measures of variability & consistency?

Which class was more consistent in their Algebra scores?

Based on measures of center, which restaurant has a longer wait time?

Based on measures of center, which club attends more car shows?

Which club has greater variability?

What inference can you make about the test scores?

What inference can you make about the test scores?

Paul compares the high temperatures in City 1 and City 2 for one week. In City 1, the range in temperature is 10°F and the IQR is 5°F. In City 2, the range in temperature is 20°F and the IQR is 5°F.

What might you conclude about the weather pattern in each city based on the ranges and IQRs?