Reference no: EM132855986

Dr. Smith has developed a new measure of height that she named "psychic height." Her new measure comes in the form of a cell phone app. The app can measure the height of nearly anything. You simply open the app on your phone and then take a picture of whatever you wish to measure. Based on the picture, the app will immediately calculate the height of the object and it will appear on the screen. Dr. Smith believes that her new measure for height is both valid and reliable. She wants to get her new app on the market as soon as possible, so she has enlisted her research assistant, June, to help her study the psychometric properties (specifically reliability and validity) of her new measure. To test these properties, June had to measure her body height, arm span, and ear size using the psychic height method on the app and using more traditional measures of height.

The traditional measures June used to measure all heights were 2 identical tape measures (measuring tape A and measuring tape B). "Identical" means that the two tape measures are the same brand and measure objects exactly the same. Below are her measurements (in inches) based on her own report and from using the Psychic Height App and traditional tape measures:

1. June's self-reported body height in inches: 65"

2. Measurements of body height using measuring tapes A and B

a. June's body height after measure herself with measuring tape A: 64.5"

b. June's body height after being measured by a fellow research assistant with measuring tape A: 64.5"

c. June's body height after being measured by the same research assistant with measuring tape B: 64.5"

d. June's body height after being measured by Dr. Smith with measuring tape B: 64.5"

3. June's body height according to the Psychic Height App (after taking one picture of herself): 12.4"

4. June's body height according to the Psychic Height App (after taking a second picture of herself): 12.4"

5. June's self-reported arm span: 60"

6. June's arm span after being measured (with measuring tape A) by a fellow research assistant: 64"

7. June's arm span according to the Psychic Height App: 3.8"

8. June's self-reported ear size: 2.5"

9. June's ear size after being measured (with measuring tape A) by a fellow research assistant: 3.4"

10. June's ear size according to the Psychic Height App: .08"

Answer the following Questions regarding this scenario. Questions should be answered by referencing the NUMBERS above. For example, if the question is "Which measurement above refers to June's self-reported height?" your answer should be "1." Similarly, utilize letters when appropriate (i.e. 2a, 2b, 2c, 2d).

1) Which of the measurements from above could be compared to evaluate test-retest reliability?

2) Which of the measurements from above could be compared to evaluate parallel forms reliability?

3) Which of the measurements from above could be compared to evaluate inter-rater reliability?

4) Which of the measurements above could be compared to evaluate whether psychic height has concurrent validity (a type of criterion validity) with the "gold standard" measure of height (i.e. a tape measure)?

5) Assuming that past research has indicated that height predicts arm span, which of the above measurements could be compared to evaluate whether psychic height has predictive validity (a type of criterion validity) with the "gold standard" measure of arm span?

6) Which of the above measurements illustrates that a measure can be reliable but not valid?

7) Can a measure be valid but not reliable?