PSYC 1010 Chapter Notes - Chapter 7: Starbucks, Dependent And Independent Variables, Sample Size Determination
29 Jun 2018
School
Department
Course
Professor
Page ! of !1 5
CHAPTER 7 HYPOTHESIS TESTING WITH Z TESTS
THE Z TABLE
RAW SCORES, Z SCORES AND PERCENTAGES
-The z table is how we tradition from one way of naming a score to another
-A way to state and test hypotheses by standardizing different
-Examples: determine the percentage given by the z score
-Step1: convert a raw score into a z score
-Step2: Look up a given z score on the z table to find the percentage of scores between
the mean and than z score
EXAMPLE 7.1
-Average height of girls 67 inch, and standard deviation of 3.19
-Average height of boys 63.80inch and standard deviation 2.66
Jessica is 66.41
-associated percentage is 33.65%
-1.) Jessica’s percentile rank- the percentage of scores below her score. add the percentage
between the mean and the positive z score to 50%
-50%+33.65%= 83.65%
-2.) Te percentage of scores above Jessica’s score
-50%-33.65%= 16.35% (above Jessica’s height)
-3.) The score at least as extreme as Jessica’s z score, in both direction
-16.35%+16.35%= 32.70%
=(66.41-63.80)
2.66
=0.98
find more resources at oneclass.com
find more resources at oneclass.com
Page ! of !2 5
EXAMPLE 7.2
-Manuel is 61.20 inches
-Mean is 67
-standard deviation 2.19
1.) Manuel’s percentile score- the percentage of scores below his score:
- Manuel’s percentile is 50%-46.5%= 3.44%
2.) The percentage of scores above Manuel’s score:
- 50%+46.56%= 96.56% so 96.5% of boy 15yrs
heights fall below
3.) The scores at least as extreme as Manuel’s z score, in both directions:
- 3.44%+ 3.44%= 6.88%
EXAMPLE 7.3
Jo is hoping to attend college, he scores a 63% percentile, we know the score is above the mea
cause 50% of scores fall below the mean, and 63 is larger than 50
63%-50%=13% (look at the z table, shows 12.93% as having a z-score of 0.33)
X = z(σ) + µ => 0.33(100)+500= 533 <—Above the mean of 500
= (61.20-67.00)
3.19
=1.82
therefore 1.83
is the z score
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The z table is how we tradition from one way of naming a score to another. A way to state and test hypotheses by standardizing different. Examples: determine the percentage given by the z score. Step1: convert a raw score into a z score. Step2: look up a given z score on the z table to find the percentage of scores between the mean and than z score. Average height of girls 67 inch, and standard deviation of 3. 19. Average height of boys 63. 80inch and standard deviation 2. 66. Jessica"s percentile rank- the percentage of scores below her score. add the percentage between the mean and the positive z score to 50% The score at least as extreme as jessica"s z score, in both direction. Manuel"s percentile score- the percentage of scores below his score: 50%+46. 56%= 96. 56% so 96. 5% of boy 15yrs heights fall below. The scores at least as extreme as manuel"s z score, in both directions:
