Practice For an SAT test  = 500  = 100

Slides:

Advertisements

Similar presentations

The Standard Normal Curve Revisited. Can you place where you are on a normal distribution at certain percentiles? 50 th percentile? Z = 0 84 th percentile?

Advertisements

For Explaining Psychological Statistics, 4th ed. by B. Cohen

Chapter 6: Standard Scores and the Normal Curve

Confidence Intervals Mon, March 22 nd. Point & Interval Estimates  Point estimate – use sample to estimate exact statistic to represent pop parameter.

Review Measures of Central Tendency –Mean, median, mode Measures of Variation –Variance, standard deviation.

Review of normal distribution. Exercise Solution.

1 Tests with two+ groups We have examined tests of means for a single group, and for a difference if we have a matched sample (as in husbands and wives)

Many times in statistical analysis, we do not know the TRUE mean of a population of interest. This is why we use sampling to be able to generalize the.

Estimation Statistics with Confidence. Estimation Before we collect our sample, we know:  -3z -2z -1z 0z 1z 2z 3z Repeated sampling sample means would.

LECTURE 17 THURSDAY, 2 APRIL STA291 Spring

Many times in statistical analysis, we do not know the TRUE mean of a population of interest. This is why we use sampling to be able to generalize the.

Population All members of a set which have a given characteristic. Population Data Data associated with a certain population. Population Parameter A measure.

Statistics 101 Chapter 10. Section 10-1 We want to infer from the sample data some conclusion about a wider population that the sample represents. Inferential.

Understanding the scores from Test 2 In-class exercise.

Confidence Intervals: The Basics BPS chapter 14 © 2006 W.H. Freeman and Company.

Copyright © 1998, Triola, Elementary Statistics Addison Wesley Longman 1 Estimates and Sample Sizes Chapter 6 M A R I O F. T R I O L A Copyright © 1998,

Review - Confidence Interval Most variables used in social science research (e.g., age, officer cynicism) are normally distributed, meaning that their.

Review Normal Distributions –Draw a picture. –Convert to standard normal (if necessary) –Use the binomial tables to look up the value. –In the case of.

Estimating a Population Mean. Student’s t-Distribution.

Confidence Intervals for a Population Mean, Standard Deviation Unknown.

Practice Page 128 –#6.7 –#6.8 Practice Page 128 –#6.7 =.0668 = test scores are normally distributed –#6.8 a =.0832 b =.2912 c =.4778.

Confidence Intervals of the Mean 2 nd part of ‘estimate of the mean’ presentation.

Confidence Intervals Chapter 6. § 6.1 Confidence Intervals for the Mean (Large Samples)

Learn: to organize and interpret data in frequency tables to organize and interpret data in frequency tables.

3.5 Applying the Normal Distribution – Z Scores Example 1 Determine the number of standard deviations above or below the mean each piece of data is. (This.

1 Probability and Statistics Confidence Intervals.

Statistical Analysis – Chapter 5 “Central Limit Theorem” Dr. Roderick Graham Fashion Institute of Technology.

Normal Distributions MM2D1d Compare the means and standard deviations of random samples with the corresponding population parameters, including those population.

m/sampling_dist/index.html.

LECTURE 26 TUESDAY, 24 NOVEMBER STA291 Fall

Many times in statistical analysis, we do not know the TRUE mean of a population on interest. This is why we use sampling to be able to generalize the.

MATH Section 7.4 Pt. 2. Recall: Look at the following example: The effect of exercise on the amount of lactic acid in the blood was examined.

10.1 Estimating with Confidence Chapter 10 Introduction to Inference.

Statistics: Unlocking the Power of Data Lock 5 Section 6.11 Confidence Interval for a Difference in Means.

Seven Steps for Doing  2 1) State the hypothesis 2) Create data table 3) Find  2 critical 4) Calculate the expected frequencies 5) Calculate  2 6)

The distribution of heights of adult American men is approximately normal with mean 69 inches and standard deviation 2.5 inches. Use the rule.

8.2 Estimating Population Means

z-Scores, the Normal Curve, & Standard Error of the Mean

CHAPTER 12 More About Regression

8.2 Estimating Population Means

Construct a probability distribution and calculate its summary statistics. Then/Now.

Inference and Tests of Hypotheses

The Normal Curve and Sampling Error

Practice For an SAT test  = 500  = 100

Assignment: Solve practice problems WITHOUT looking at the answers.

Estimating the Population Mean Income of Lexus Owners

Standard and non-standard

MATH 2311 Section 7.4.

Theoretical Normal Curve

Week 10 Chapter 16. Confidence Intervals for Proportions

Hypothesis Testing: Two Sample Test for Means and Proportions

MATH 2311 Section 7.4.

Distribution of a Difference in Means

Module 26: Confidence Intervals and Hypothesis Tests for Variances for Two Samples This module discusses confidence intervals and hypothesis tests for.

MATH 2311 Section 7.4.

CHAPTER 16: Confidence Intervals: The Basics

Confidence Interval (CI) for the Mean When σ Is Known

Frequency Tables/ Two way tables

Calculating Probabilities for Any Normal Variable

Lecture: statistical significance.

Practice The Neuroticism Measure = S = 6.24 n = 54

CHAPTER 12 Inference for Proportions

BUSINESS MATHEMATICS & STATISTICS.

CHAPTER 12 Inference for Proportions

Practice #7.7 #7.8 #7.9. Practice #7.7 #7.8 #7.9.

MATH 2311 Section 7.4.

Accuracy of Averages.

Scatterplots and Two-Way Tables

Confidence Intervals Usually set at 95 % What does that mean ?

MATH 2311 Section 7.4.

Presentation transcript:

Practice For an SAT test  = 500  = 100 What is the probability that a sample of 65 people will have a mean SAT score below 525?

Step 1: Sketch out question -3 -2 -1 0 1 2 3

Step 2: Calculate the Standard Error 100 / 65 = 12.40 -3 -2 -1 0 1 2 3

Step 3: Calculate the Z score (525 - 500) / 12.40 = 2.02 -3 -2 -1 0 1 2 3

Step 4: Look up Z score in Table Z = 2.02; Column B =.4783 .50 .4783 -3 -2 -1 0 1 2 3

Practice There is a .9783 probability that a sample of 65 people would have a mean SAT under 525

Practice In a large corporation, the mean salary for all males with 3 to 5 years of experience was $28,000. Salaries (expressed in thousands) for a random sample of 10 women also having 3 to 5 years of experience were: 24, 27, 31, 21, 19, 26, 30, 22, 15, 36 Construct the 95% confidence interval for women and interpret what this means relative to the mean salary of males.

Practice M = 25.1 SE = 1.97 t(9) = 2.262 20.64 to 29.56 20,640 to 29,560

Practice Old book - 8.30 New book – 8.29

Practice SE = 1.0 t = 2.064 T1 = 5.936 to 10.064 T2 = 3.936 to 8.064

Practice On the next test I will give an A to the top 5 percent of this class. The average test grade is 56.82 with a SD of 6.98. How many points on the test did you need to get to get an A?

Step 1: Sketch out question .05

Step 2: Look in Table C In column C get as close to .05 as you can and find the corresponding Z score = 1.64 .05

Step 3: Find the X score that goes with the Z score Must solve for X X =  + (z)() 68.26 = 56.82 + (1.64)(6.98)

Step 3: Find the X score that goes with the Z score Must solve for X X =  + (z)() 68.26 = 56.82 + (1.64)(6.98) Thus, a you need a score of 68.26 to get an A

Practice 6.22

Practice X = Stanford-Binet Y = WAIS b = .80 (15 / 16) = .75 Y = 25 + (.75)X 73.75 = 25 + (.75)65 It’s a bad idea to use the same cut off score for these two tests

Practice 6.5

Practice Page 96 # 5.5 r = .51

Practice Old book - 8.12 and 8.13 New book – 8.11 and 8.12

N 1 2 4 8 .5 16 .25 64 .125 As N (sample size) increases the standard error decreases!

NO CLASS ON FRIDAY 10/7