Ch 11 PPT

Please make a pile of your pink noteguide & hw (textbook and Ch 7 review questions) after you’ve checked your work!

x 22 20 24 32-14 = 18 measure that is used to quantify the amount of variation or dispersion of a set of data σ “sigma” 5.67

Solving for Stats on the Calculator Step 1: Hit “Stat and then “Edit” Step 2: Input data in the lists

Step 4: Make sure L1 is selected and click “Calculate ” Step 3: Going back to “stat” scroll over to “CALC” and hit “1-Var Stats”

What are outliers? In the following Data, which numbers could be considered “outliers” and why? 2, 14, 17, 18, 19, 20, 24, 24, 30, 32, 101 thing differing from all other members of a particular group or set.

You Try! The data set below gives the waiting times (in minutes) of 10 students waiting for their Pedone’s Pizza on a normal lunch day: 4, 8, 12, 15, 3, 2, 6, 9, 8, 7 Find the mean, median, and mode, and Standard Deviation. Use appropriate symbols. You go to Pedone’s and end up having to wait 35 minutes! An outlier, for sure. Calculate the new mean, median, and mode, and Standard Deviation. ********Which measure of central tendency does the outlier affect the most? The least?

HW

HW Given the table, make a histogram using five intervals beginning with 0-9, that shows the distribution of waiting times at Cheesecake Factory . Then describe the shape of the distribution.

Normal Distributions - One way people study data is by a normal distribution, which is when data is modeled by a bell-shaped curve called a normal curve that is symmetric about the mean. - Sometimes a data set might not seem like it would fit a normal distribution, but if you add more and more data points, it begins to resemble one.

100% 68% .15% .15% 95% 99.7%

EX 1: For a randomly selected data value on a normal distribution, find the probability that this data point lies somewhere between the mean and two s.d. from the mean. In other words, find:

The blood cholesterol readings for a group of women are normally distributed with a mean of 172 mg/dl and a standard deviation of 14 mg/dl. What percentage of women have readings between 158 and 186? Readings higher that 200 are considered undesirable. About what percentage of readings in this data set are undesirable? Draw this picture on the board.

What if you were asked this question…. (Question from before) The blood cholesterol readings for a group of women are normally distributed with a mean of 172 mg/dl and a standard deviation of 14 mg/dl. What percentage of women have readings at or below 157?

What if you were asked this question (Question from before) The blood cholesterol readings for a group of women are normally distributed with a mean of 172 mg/dl and a standard deviation of 14 mg/dl. What percentage of women have readings at or below 157?

The number of seals observed during a series of studies shows a normal distribution with a mean of 73 seals during a study and a standard deviation of 14.1 seals. Find the probability that at most 50 seals were observed during a survey. Step 1: Find the z-score corresponding to an x-value of 50 Step 2: Use the table to find P(x ≤ 50)

You Try! A normal distribution has a mean of 64 and a standard deviation of 7. Use the standard normal table on pg 769 to find the indicated probability for a randomly selected x-value from the distribution. P(x ≤ 68) c) P(x ≥ 64) e) P(45 ≤ x ≤ 65) B) P(x ≤ 54) d) P(x ≥ 59)

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