Consider the 4 scatterplots below:   a.                                b.       c.                                 d.           Match the value of the correlation coefficient to the scatterplot. 1.   r = 0              plot:  2.   r = -0.7         plot:  3.   r = 0.9           plot:  4.   r = -0.99       plot:   

The analysis of variance (ANOVA) is an inferential method that is used to test the equality of

A normal curve is symmetric about___________________.

In a certain class the final grade is determined by two midterm exams, each of which counts for 25% of the grade, a class project which counts for 15% of the grade, homework which counts for 10% of the grade, attendance which counts for 5% of the grade and a final exam which counts for 20% of the grade.  If you have the following scores at the end of the semester, what is your final average? Data Table Grade Category Student Grade Midterm 1 86 Midterm 2 72 Project 93 Homework 82 Attendance 100 Final exam  85

A study is to be done to compare math achievement in the two different middle schools in a certain city.  A random sample of middle school students at North Middle School is chosen and their math achievement scores recorded.  A random sample of middle school students at South Middle School is chosen their scores recorded.  The data is provided below.  Assume that the data meets the conditions to calculate a confidence interval.  North:  45     50     60     63     52     57     51     44     55    57 South:  48     62     73     70    58     64     58     42      69    62 1. Are these considered dependent or independent populations?  2. What is the point estimate of the difference in the mean math achievement scores of students at North and South Middle Schools?  3. We are 95% confident that the difference in the mean math achievement scores at North and South Middle school is between and . 4. Because the interval we .   

A college instructor is teaching a summer class and believes that there is an association between the temperature and the number of students absent.  The instructor randomly chooses a sample of days and records the temperature, in degrees Fahrenheit, and the number of students absent.  Temp. oF (x) 72 85 91 90 88 98 75 100 80 Number Absent (y) 3 7 10 10 8 15 4 10 5 1. Find the linear correlation coefficient r for this data set.  Round to three decimal places. 2. A hypothesis test is to be done to determine if there is linear correlation between these two variables.  The null and alternative hypotheses are given below.  Use a 0.05 level of significance.          

The 95% confidence interval for the mean amount spent by a U.S. household on gas per month is found to be $220 to $290. This interval was based on a random sample of 100 U.S. households. For each of the following changes determine whether the width of the confidence interval would increase, decrease or the change would have no effect.  Change the sample size from 100 to 200.  Change the confidence level from 95% to 99%    

A sample of High School students were surveyed and asked, “how many days this week have you been late to school?”  The data is recorded in the table below. Which of the following is the correct histogram for this data set?

A confidence interval is calculated for the difference in the mean cost of taking a morning plane from Los Angeles to San Francisco and the mean cost of taking an afternoon plane from Los Angeles to San Francisco.  The resulting 95% confidence interval for the difference in the means is ($12, $25).  Based on this interval complete the following sentence.  Since the 95% confidence interval  we can conclude that  

A random sample of 220 SMC students determined that 65 of them had dependent children.  A random sample of 275 West LA  College students determined that 72 of them had dependent children.  Use this information to complete the following.  You can assume that the conditions to calculate the confidence interval are met.  Choose the best answer in each case.  1. Are these considered dependent or independent populations?  2. What is the point estimate of the difference in the proportions of SMC students and West LA students that had dependent children?  3. We are 95% confident that the difference in the proportion of SMC students and West LA College students who had dependent children is between and 4. Because the interval we .