1 / 19

Height and Weight

Height and Weight. Presented by Clarence Cheng & Kehinde Opere. Hypotheses – Height (z- and t-tests). Lower 1–tail test Null hypothesis H o : the average height for 2004 SCSU SDP students is not significantly different from 169 cm

alexia
Télécharger la présentation

Height and Weight

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Height and Weight Presented by Clarence Cheng & Kehinde Opere

  2. Hypotheses – Height (z- and t-tests) • Lower 1–tail test • Null hypothesis Ho: the average height for 2004 SCSU SDP students is not significantly different from 169 cm • Alternative hypothesis Ha: the average height is less than 169 cm Or… • H0: μh = 169 cm • Ha: μh < 169 cm • Upper 1–tail test • Null hypothesis Ho: see above • Alternative hypothesis Ha: the average height is greater than 169 cm Or… • H0: μh = 169 cm • Ha: μh > 169 cm

  3. Hypotheses – Height cont. (z- and t-tests) • 2–tail test • Null hypothesis H0: see above • Alternative hypothesis Ha: the average height is not 169 cm Or… • H0: μh = 169 cm • Ha: μh ≠ 169 cm • α = .05, or 5% (this will apply to all following slides)

  4. Testing… (z) • 1-Tail: • zα = 1.645 for upper 1-tail test and -1.645 for lower 1-tail test • z = (xbar – μ)/(s/√n) ≈ .2093 • Because -1.645 < .2093 < 1.645, H0 can be accepted as true for both the upper and lower 1-tailed z tests. • In other words, with a 5% chance of committing a Type I error, the average height of 2004 SCSU SDP students is not significantly different from 169 cm. • To avoid repetition, the preceding conclusion will not be printed on other slides in this presentation with the title Testing…

  5. Testing… (z) • 2-Tail: • zα = 1.96 for 2-tail test • z = (xbar – μ)/(s/√n) ≈ .2093 • Because -1.96 < .2093 < 1.96, H0 can be accepted as true for the 2-tailed z test.

  6. Testing… (t) • 1-Tail: • tα = 1.782 for upper 1-tail test and -1.782 for lower 1-tail test • t = (xbar – μ)/(s/√n) ≈ .2093 • Because -1.782 < .2093 < 1.782, H0 can be accepted as true for both the upper and lower 1-tailed t tests.

  7. Testing… (t) • 2-Tail: • tα = 2.179 for 2-tail test • t = (xbar – μ)/(s/√n) ≈ .2093 • Because -2.179 < .2093 < 2.179, H0 can be accepted as true for the 2-tailed t test.

  8. Descriptive Statistics – Height • Mean: 169.4615 • Median: 170 • Mode: 170 • Range: 30 • Standard Deviation: 7.9516

  9. Hypotheses – Weight (z- and t-tests) • Lower 1–tail test • Null hypothesis H0: the average weight (in kg) for 2004 SCSU SDP students is not significantly different from 72 kg • Alternative hypothesis Ha: the average weight is less than 72 kg Or… • H0: μw = 72 kg • Ha: μw < 72 kg • Upper 1–tail test • Null hypothesis H0: see above • Alternative hypothesis Ha: the average weight is more than 72 kg Or… • H0: μw = 72 kg • Ha: μw > 72 kg

  10. Hypotheses – Weight cont. (z- and t-tests) • 2-tail test • Null hypothesis H0: see above • Alternative hypothesis Ha: the average weight is not 72 kg Or… • H0: μw = 72 kg • Ha: μw ≠ 72 kg

  11. Testing Again… (z) • 1-Tail: • zα = 1.645 for upper 1-tail test and -1.645 for lower 1-tail test • z = (xbar – μ)/(s/√n) ≈ -.7736 • Because -1.645 < -.7736 < 1.645, H0 can be accepted as true for both the upper and lower 1-tailed z tests. • In other words, with a 5% chance of committing a Type I error, the average weight of 2004 SCSU SDP students is not significantly different from 72 kg. • To avoid repetition, the preceding conclusion will not be printed on other slides in this presentation with the title Testing Again…

  12. Testing Again… (z) • 2-Tail: • zα = 1.96 for 2-tail test • z = (xbar – μ)/(s/√n) ≈ .2093 • Because -1.96 < .2093 < 1.96, H0 can be accepted as true for the 2-tailed z test.

  13. Testing Again… (t) • 1-Tail: • tα = 1.782 for upper 1-tail test and -1.782 for lower 1-tail test • t = (xbar – μ)/(s/√n) ≈ -.7736 • Because -1.782 < -.7736 < 1.782, H0 can be accepted as true for both the upper and lower 1-tailed t tests.

  14. Testing Again… (t) • 2-Tail: • tα = 2.179 for 2-tail test • t = (xbar – μ)/(s/√n) ≈ -.7736 • Because -2.179 < -.7736 < 2.179, H0 can be accepted as true for the 2-tailed t test.

  15. Descriptive Statistics – Weight • Mean: 69.0546 • Median: 65.4 • Mode: N/A • Range: 36.82 • Standard Deviation: 13.7280

  16. A Graph Height vs. Weight – Scatterplot

  17. Another Graph Height vs. Weight – Line Graphs

  18. So, What Did That Mean?(the graphs) • The scatterplot shows there is basically no correlation between height and weight. The points are for the most part evenly spread. Thus, height and weight are likely not related. • The line graphs are further support for this notion, as the graphs tend to increase and decrease both simultaneously and inversely, showing they are independent of each other. • The correlation coefficient for the two data sets is .0459 – this demonstrates the little correlation between height and weight as well.

  19. Note… Calculations of means, medians, modes, ranges, standard deviations, and z and t values and the making of the graphs were done in Microsoft Excel.

More Related