Lecture 9, 9-29.pptx - Plans about Midterm(10\/6 \u2022 This week \u2022 Tuesday 9\/29 Lecture 9 \u2022 Tuesday 9\/29 HW 5 posted after Lecture 9(different from

# Lecture 9, 9-29.pptx - Plans about Midterm(10/6 u2022...

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This week Tuesday 9/29: Lecture 9 Tuesday 9/29: HW 5 posted after Lecture 9 ( different from usual ) HW 5 due Friday 10/2 at 9:30 AM ( different from usual ) Lab 5 posted Friday 10/2 at 10 AM ( different from usual ) No class Thursday 10/1 Next week Tuesday 10/6: Midterm 1 (time = 2 hours) Any 2 consecutive hours between 7 AM --- 11 PM Exam at CatCourses Thursday 10/8: Lecture as usual Plans about Midterm (10/6)
Coverage: Ch 1-3 50 questions = 40 multiple choice + 10 fill-in The best way to prepare: Review all the lecture slides Pause & think questions in class Re-do all the HW Exam questions will be very similar to HW questions! Next week’s Tuesday 10/6: Midterm 1 You take exam at CatCourses Any 2 consecutive hours between 7 AM --- 11 PM Not OK : 9-10am and then 4-5pm ( must be 2 consecutive hours ) Timer will keep running even leave if you leave CatCourses Midterm : Next week’s Tuesday 10/6
PSY 010: Analysis of Psychological Data Lecture 9: Normal distribution basics Keke Lai 9/29/2020
Today Normal distribution Use normal distribution to find probabilities Reading: Ch 3
Review Z-score: Based on Central tendency & Variability Provides a context for understanding X Compare scores from different data sets Standard score vs Raw score “z = 2” means “X is 2 standard deviations above the mean” “X is 1 std dev unit below the mean” means “z= ” Q: An exam has µ = 60 and σ = 20. My score is 80. How far is my score from the mean? A: It’s asking what my z-score is.
The std dev () is just a number 1.6 std dev units = My Logic score is 1 std dev above the mean = “ Raw score is 7 pt above the mean = “ Z-score is 1 My Math score is 1/3 std dev below the mean = “ Math raw score is 2 pt below the mean = “ Z-score is -1/3
Pause and thinkIf X is 1.5 standard deviation units below the mean, what’s the Z-score for X? (A) Z= 1.5(B) Z= 1.5 SD units (C) Z= 1.5(D) Z = 1.5 SD units
Pause and thinkIf X is 1.5 standard deviation units below the mean, what’s the Z-score for X?
If I got 70 from an exam and I’m 1 standard deviation below the mean, what’s my Z-score? We know the mean=80 and SD=10 for all the exam scores.
If I got 70 from an exam and I’m 1 standard deviation below the mean, what’s my Z-score? We know the mean=80 and SD=10 for all the exam scores.
From descriptive to inferential stats So far things have been all about descriptive statistics Central tendency Variability Symmetric vs skewed We are given a data set. Then we try to extract information from this data set. In practice, we almost never have the data set of real interest (population) 16 17 20 20 22 23 25 27 28 28 28 29 29 30 30 31 31 31 31 32 32 33 33 33 34 34 35 35 35 35 36 36 36 36 36 36 37 37 37 37 37 37 38 38 38 38 38 39 39 39 39 39 40 40 40 40 40 40 40 41 41 41 41 41 41 41 42 42 42 42 42 42 42 42 42 42 42 43 43 43 43 43 43 43 43 44 44 45 45 45 45 45 45 45 45 45 45 45 46 46 46 46 46 46 47 47 47 47 47 48 48 48 48 48 48 48 48 48 48 48 49 49 49 49 49 49 49 49 49 49 50 50 50 50 50 50 51 51 51 51 52 52 52 52 52 52 52 52 52 53 54 54 54 54 55 55