PSYC 2019H Assignment 1 (WI2026)

PSYC 2019H Assignment 1 (WI2026)

10% of final grade

Last Name, First Name:  _____________________________________

Student ID#: __________________________

Crowdmark Submission Instructions:

For those who choose to write the assignment digitally: Once you have completed the assignment, please make sure that each Numbered Section (Sections 1, 2, 3, and 4) starts on its own page, and then save your document as a PDF for submission to Crowdmark. Please use the Bulk Upload option and then assign the pages for each section to their appropriate submission box.

For those who choose to print out and write the assignment physically: You will need to use JASP to complete section 4 of the assignment, but the rest of the assignment can be handwritten. To submit your physical assignment, please take a clear picture of each page of your assignment and submit those images to the Crowdmark Submission page using the Bulk Upload option, assigning your images for each section to the appropriate submission box. Make sure that you can read your responses in the images you submit (e.g., they are not too small), or they will not be marked. 

If you are unsure how to use the Bulk Upload option,links to a how-to video explaining the process are available on the Crowdmark tab on Blackboard, as well as on the Crowdmark submission page for this assignment.

Section 1: Central Tendency and Variability (15 marks):

Below is a list of 10 numbers. Calculatethe answers to the following questions by hand using the formulas provided in Chapter 4 or in the lecture on Central Tendency and Variability. REMEMBER: Round to TWO decimal places at each step of your calculations. You might even have to add a trailing 0 in some cases (e.g., 3.6 should be 3.60). Show your work in the table below (like we did in lecture and lab). Record all answers in the spaces provided.

45, 19, 29, 28, 17, 34, 27, 22, 18, 34

1a) What is the meanof X (1 mark)?

1b) What is the medianof X (1 mark)?

1c) What is the modeof X (1 mark)?

1d) What is the 10% trimmed mean of X(1 mark)?

1e) What is the Sum of the Squared Differences from the Meanfor X (1 mark)?

1f) What is the varianceof X, using the formula from Chapter 4 of your text (1 mark)?

1g) What is the standard deviationof X, using the formula from Chapter 4 of your text(1 mark)?

1h) What would the mean become if you changed the number 45in the table above to 70 (1 mark)?

1i) What would the median become if you changed the number 45in the table above to 70 (1 mark)?

1j). What would the 10% trimmed mean be if you changed the number 45 in the table above to 70 (1 mark)?

1k) Why does the above change (from 45 to 70) affect the mean, trimmed mean, and median so differently (2 marks)?

1l) What would the Standard Deviation become if you changed the number 45 above to 70 (1 mark)?

1m) Did the standard deviation change much (1 mark)? Explain why or why not (1 mark):

Section 2: z Scores (8 marks)

Morty wrote a Math test and an English test, and he’s curious to know in which courseis he doing better. The descriptive statistics for his two classes are below. REMEMBER: Round to TWO decimal places at each step of your calculations.

2a) Compare the value of the standard deviations for the two classes (1 mark).  What do these differences tell you about the two distributions (1 mark):

2b) Looking at the descriptive statistics in the table above, what shape would the distribution of Math scores be and how do you know this (1 mark)?

Morty’s grade was 84 in both classes. Calculate thezscore for his grade in both classes. Make sure to show your work.

2c) Morty’s Math zscore (1 mark) =

2d) Morty’s English zscore (1 mark) =

2e) Briefly comment on the difference in zscores (1 mark):

2f) In which class did Morty perform better, relative to the rest of the class? You may want to draw a graph to visualize where the z scores fall on the distribution. Briefly explain your answer (1 mark):

2g) Morty’s friend, Sam, has a z score of 1.44 on the Math Test.  What is Sam’s raw score on this test?REMEMBER: Show your work. Round to TWO decimal places at each step of your calculations AND round your final answer to a whole number (no decimal places) (1 mark)

Section 3: Using The Normal Curve (3 marks).

The following questions all use IQ scores, with a Mean (m) of 100 and a standard deviation (s) of 15. You will need to consult the normal curve diagram on page 165 of your textto help determine these answers.

3a) What percentage of the distribution is above a z score of 0 (1 mark)?

3b) What percentage of IQ scores is between -2 and +1 z scores (1 mark)?

3c) What percentage of the distribution falls above a raw IQ score of 115 (1 mark)?

Section 4:Descriptive Statistics and Plots in JASP (8 marks)

Download the data file called ‘Assignment 1.csv’. Open this file in JASP and perform the following tasks and answer the following questions. When asked to paste an output from JASP, make sure to add your name in the title of the output or as a note (as shown in the first lab).

4a) Have JASP compute the following statistics for the variable ‘Score’: Number of valid cases, Number of missing cases, Mean, Median, Standard deviation, Minimum, and Maximum. Paste the output below here (2 marks).

4b) Generate a histogram of the variable ‘Score’.  Paste the output below here (1 mark):

4c) What shape is the distribution of scores (1 mark) and how do you know this (1 mark)?

4d) Generate a boxplot of the variable ‘Score’ and paste below here (1 mark):

4e) Are there any outliers present in the boxplot (1 mark) and how do you know this (1 mark)?

Total = 34