Janet Meinke

University of Southern Mississippi
Instructor

Biography

I’ve taught Algebra 1, Algebra 2, Geometry, PreCalculus, Analytic Geometry, Trigonometry, Calculus AB & BC, Prob&Stats and SAT math review. On the community college level, I’ve taught College Algebra and Prob&Stat. I began teaching in 1987 and have been told by many students that I explain topics very well.

Education

MS Curriculum & Instruction (Mathematics)
University of Southern Mississippi

Educator Statistics

Numerade tutor for 6 years
21 Students Helped

Topics Covered

Mastering the Basics of Parametric Equations: A Comprehensive Guide
Polar Coordinates: Understanding the Basics and Applications
Introduction to Conic Sections
Unlock Insights with Data-Driven Graphs & Statistics
Maximizing Accuracy with Effective Sampling and Data Analysis

Janet's Textbook Answer Videos

12:35
The Practice of Statistics for AP

Larger sample Suppose that the blood cholesterol level of all men aged 20 to 34 follows the Normal distribution with mean $\mu=188$ milligrams per deciliter $(\mathrm{mg} / \mathrm{dl})$ and standard deviation $\sigma=41 \mathrm{mg} / \mathrm{dl}$
(a) Choose an SRS of 100 men from this population What is the sampling distribution of $\overline{x} ?$
(b) Find the probability that $\overline{x}$ estimates $\mu$ within $\pm 3 \mathrm{mgldl}$ . This is the probability that $\overline{x}$ takes a value between 185 and 191 $\mathrm{mg} / \mathrm{dl} .$ ) Show your work.
(c) Choose an SRS of 1000 men from this population. Now what is the probability that $\overline{x}$ falls within $\pm 3 \mathrm{mg} / \mathrm{dl}$ of $\mu ?$ Show your work. In what sense is the
larger sample "better"?

Chapter 7: Sampling Distributions
Section 3: Sample Means
Janet Meinke
07:26
The Practice of Statistics for AP

Stop the car! A car company has found that the lifetime of its disc brake pads varies from car to car
according to a Normal distribution with mean $\mu=55,000$ miles and standard deviation $\sigma=4500$ miles. The company installs a new brand of brake pads on an SRS of 8 cars.
(a) If the new brand has the same lifetime distribution as the previous type of brake pad, what is the
sampling distribution of the mean lifetime $\overline{x} ?$
(b) The average life of the pads on these 8 cars turns out to be $\overline{x}=51,800$ miles. Find the probability that the sample mean lifetime is $51,800$ miles or less if the lifetime distribution is unchanged. What conclusion would you draw?

Chapter 7: Sampling Distributions
Section 3: Sample Means
Janet Meinke
08:00
The Practice of Statistics for AP

Bottling cola A bottling company uses a flling machine to fill plastic bottles with cola. The bottles are supposed to contain 300 milliters $(\mathrm{ml}) .$ In fact, the contents vary according to a Normal distribution with mean $\mu=298 \mathrm{ml}$ and standard deviation $\sigma=3 \mathrm{ml}$
(a) What is the probability that an individual bottle contains less than 295 $\mathrm{ml}$ ? Show your work.
(b) What is the probability that the mean contents of six randomly selected bottles is less than 295 $\mathrm{ml}$ ? Show your work.

Chapter 7: Sampling Distributions
Section 3: Sample Means
Janet Meinke
09:35
The Practice of Statistics for AP

ACT scores The composite scores of individual students on the ACT college entrance examination in
2009 followed a Normal distribution with mean 21.1 and standard deviation 5.1
(a) What is the probability that a single student randomly chosen from all those taking the test scores
23 or higher? Show your work.
(b) Now take an SRS of 50 students who took the test. What is the probability that the mean score $\overline{x}$ of these students is 23 or higher? Show your work.

Chapter 7: Sampling Distributions
Section 3: Sample Means
Janet Meinke
02:00
The Practice of Statistics for AP

What does the CLT say? Asked what the central limit theorem says, a student replies, "As you take larger and larger samples from a population, the histogram of the sample values looks more and more Normal." Is the student right? Explain your answer.

Chapter 7: Sampling Distributions
Section 3: Sample Means
Janet Meinke
01:37
The Practice of Statistics for AP

The CLT applet Go to the textbook Web site (www whfreeman.com/tps 4 $\mathrm{e} )$ and click on
"Statistical Applets." Launch the Central Limit Theorem applet. You should see a screen like the one shown here. Click and drag the slider to change the sample size, and watch how the density curve for the sampling distribution changes with it. Write a few sentences describing what is happening.

Chapter 7: Sampling Distributions
Section 3: Sample Means
Janet Meinke
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