Chapter 3.3 Measures of Position, Study notes of Physics

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Chapter 3.

Measures of Position

Define the following: z score, percentiles, inner quartile range (IQR), deciles

ex: Paolo scored 65 on his Algebra 2 test where the mean was 50 and S.D. was 10; he then scored 30 on his English test with a mean of 25 and S.D. of 5. Compare the relative positions of the tests.

Percentiles used in education and healthrelated fields percentile (^) ≠percentage percentile indicates position relative to others tested graph is similar to ogive (cumul. freq. graph) with freq. converted to %

ASSIGNMENT p. 161 #

ex: Mrs. Putzier gave a 20 point quiz to 3rd period Geometry (10 students). The scores were: 18, 15, 12, 6, 8, 2, 3, 5, 20, 10 a.) Find the percentile rank of a score of 12. b.) Find the value corresponding to the 25th percentile. 60th percentile. c = n p 100 n = total # values p = percentile Note: If c is decimal, round up and use the c th value from the list. If c is a whole number, find the average of the c th and (c+1) th value. Percentile Formula Percentile = (#^ of^ values^ <^ X)^ +^ 0.5 100 total # of values

Outliers To identify any outliers:

1. Order data, find Q 1 and Q 3.
2. Find IQR.
3. Multiply IQR by 1.5.
4. Subtract value in step 3 from Q 1 and add to Q 3.
5. Any value smaller or larger than 2 numbers in step 4 are outliers. ex: Check for outliers. 5, 6, 12, 13, 15, 18, 22, 50

ASSIGNMENT p. 162 #15, 1819, 2425, 30