Preview

Webcalc Ii

Better Essays
Open Document
Open Document
1569 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Webcalc Ii
Z test &One sample t-test

1. A researcher is interested in whether students who attend private high schools have higher average SAT Scores than students in the general population. A random sample of 90 students at a private high school is tested and and a mean SAT score of 1030 is obtained. The average score for public high school student is 1000 (σ= 200).

a. Is this a one- or two tailed test? Key word “whether”.This is a two-tailed hypothesis test. Researcher wants to know “whether” the groups being compared differ, but does not predict the direction of the difference. The mean of the sample will be different from or unequal to the mean of the general population. b. What are H0 and Ha for this study? The researcher predicts a difference in SAT scores between private high schools and those in public high schools, but the direction of the difference is not predicted. Those in private high schools would be expected to have either higher or lower SAT scores but not the same SAT score as the public high schools. The statistical notation for this two-tailed test is H0:µ0 = µ1, or µPrivate High School = µ Public High School Ha:µ0 = µ1, or µPrivate High School ≠ µ Public High School c. Compute Zobt The mean SAT score of the public high school (µ) is 1000, with a standard deviation (σ) of 200; for private high school in the sample (N=90), mean SAT score is 1030. σx= σ/Square Root of N = 1000/Square Root of 200 = 1000/14.14 = 70.72 z= X - µ/σx= 1030 – 1000/70.72 = 30/70.72 = .42 Zobt= .42 [All calculations were done by using hand and/or 10 digit calculator.] d. What is the Z critical value (Z cv ) using a 0.05 alpha level? According to table A.2 0.05 alpha level is 1.96 e. Should H0 be rejected? What should the researcher conclude? Zobthas to be as large or larger than Z cvto reject H0 Zobt= .42 Z cv= 1.96 Zobt< Z cv, therefore H0 should be

You May Also Find These Documents Helpful

  • Good Essays

    Assignment 4

    • 2820 Words
    • 14 Pages

    3. In testing the difference between the means of two independent populations, if neither population is normally distributed, then the sampling distribution of the difference in means will be approximately normal provided that the sum of the sample sizes obtained from the two populations is at least 30. true…

    • 2820 Words
    • 14 Pages
    Good Essays
  • Better Essays

    Our group decided to research the impact of single parent versus two parent homes on student test scores. To investigate, we will be using CRCT scores from 5th grade students attending Hutchinson Elementary School in Atlanta. Our research question is as follows: At Hutchinson Elementary School, is there a significant difference in the Social Studies CRCT scores of 5th grade students from two parent households compared to children who are being raised by a single parent?…

    • 2835 Words
    • 12 Pages
    Better Essays
  • Good Essays

    A Hypothesis Is a Claim

    • 805 Words
    • 4 Pages

    e.g., The average diameter of a manufactured bolt is not equal to 30mm ( H1: μ ≠ 30 )…

    • 805 Words
    • 4 Pages
    Good Essays
  • Good Essays

    Exercise Week 3

    • 550 Words
    • 2 Pages

    2. Those who apply for admission to OSU’s graduate college have to take and report their GMAT or GRE scores. In one population, GMAT scores are normally distributed with mean of 540 and s.d of 100, whereas GRE scores are normally distributed with a mean of 500 and s.d of 80. Who has a better score, a student with 600 on the GRE or a student with 660 on the GMAT? Why?…

    • 550 Words
    • 2 Pages
    Good Essays
  • Good Essays

    Abolish Sat

    • 427 Words
    • 2 Pages

    In “Abolish the SAT” by Charles Murray, Murray argues that there's no benefit in keeping SAT test, thus it should be demolished. The author supports this point by comparing and analyzing the relationship between high school grades, SAT scores, and freshman grades in college, stating how the meaning of “SAT” has changed over time, and stating that wealthy kids have advantages of getting high scores on SAT than those who are poor.…

    • 427 Words
    • 2 Pages
    Good Essays
  • Good Essays

    Adf-Realtes

    • 2143 Words
    • 18 Pages

    Topics Distribution of the sample mean. Central Limit Theorem. Confidence intervals for a population mean. Confidence intervals for a population proportion. Sample size for a given confidence level and margin of error (proportions). Poll articles. Hypotheses tests for a mean, and differences in means (independent and paired samples). Sample size and power of a test. Type I and Type II errors. You will be given a table of normal probabilities. You may wish to be familiar with the follow formulae and their application.…

    • 2143 Words
    • 18 Pages
    Good Essays
  • Good Essays

    PSY 315 WEEK 4 PROBLEMS

    • 871 Words
    • 4 Pages

    14. Based on the information given for each of the following studies, decide whether to reject the null hypothesis. For each, give (a) the Z-score cutoff (or cutoffs) on the comparison distribution at which the null hypothesis should be rejected, (b) the Z score on the comparison distribution for the sample score, and (c) your conclusion. Assume that all populations are normally distributed.…

    • 871 Words
    • 4 Pages
    Good Essays
  • Satisfactory Essays

    Results from previous studies showed 79% of all high school seniors from a certain city plan to attend college after graduation. A random sample of 200 high school seniors from this city reveals that 162 plan to attend college. Does this indicate that the percentage has increased from that of previous studies? Test at the 5% level of significance.…

    • 1239 Words
    • 5 Pages
    Satisfactory Essays
  • Satisfactory Essays

    1) The Cranston Hardware Company is interested in estimating the difference in the mean purchase for men customers versus women customers. It wishes to estimate this difference using a 95 percent confidence level. If the sample size is n = 10 from each population, the samples are independent, and sample standard deviations are used, and the variances are assumed equal, then the critical value will be t = 2.1009.…

    • 15053 Words
    • 85 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Math 533 Part B

    • 1217 Words
    • 6 Pages

    I will use a = .05 as the significance level, and observing the sample size of n < 30 which tells me I need to use a Z-Test to find the mean of this test and the hypothesis. As the alternative hypothesis is Ha: u < $45,000, the given test is a one-tailed Z-Test.…

    • 1217 Words
    • 6 Pages
    Satisfactory Essays
  • Good Essays

    The hypothesis is two-tailed since we are using a significance level of 0.05. Therefore, no matter the direction you are hypothesizing the researcher is testing for the possibility on both sides since the alternative is: Ha: μ≠ 75 it is two-tailed…

    • 406 Words
    • 2 Pages
    Good Essays
  • Good Essays

    -0.4903 is less than 3, flatter than a normal distribution with a wider peak. The probability for extreme values is less than for a normal distribution, and the values are wider spread around the mean. Similarly the negative skewness i.e. -0.035014 shows that the Left skewed distribution, most values are concentrated on the right of the mean, with extreme values to the left. Also Length of Stay have smaller standard deviation i.e. 2.61357 therefore smaller standard deviation indicates that there is less dispersion & less variability in the lengths of stay for cardiac patients. Also we see that the average value of 7.7 of the Lengths of stay for cardiac patients. Also we see that maximum 13 no of Lengths of Stay and minimum 2 no of Lengths of Stay (Weiss,…

    • 650 Words
    • 3 Pages
    Good Essays
  • Better Essays

    The Stroop Effect

    • 1563 Words
    • 7 Pages

    This is a two tailed hypothesis The null hypothesis was that there would be no difference in the response times of the two conditions.…

    • 1563 Words
    • 7 Pages
    Better Essays
  • Powerful Essays

    Elert, Glenn. "The SAT Aptitude or Demographics?" Hypertextbook. N.p., 5 May 1992. Web. 25 Oct. 2012.…

    • 1821 Words
    • 8 Pages
    Powerful Essays
  • Better Essays

    Traffic Problems

    • 1077 Words
    • 5 Pages

    We collect data through questionnaire. Our sample space is 30. We distributed 30 questionnaires among the students of Air University. We collected data from both male…

    • 1077 Words
    • 5 Pages
    Better Essays