MATH 131
Lab 3 8/16 The goal of this lab is to find descriptive statistics for your quantitative data.
Part 1: V2, Quantitative Data
(3 points) Use the list of all 40 numbers from Lab 1, column V2 for this part of the lab.
A. Identify the name of the quantitative variable V2 that you are using __________________.
B. Use StatCrunch or Minitab to find
Mean
Median
Mode
Standard Deviation Minimum Value
Maximum Value
Q1
Q3 C. Using the appropriate numbers from B above, make a box-and-whisker plot for your data.
What does this plot tell you about your data? (2 Points) D. Looking at your list in B, list your Minimum, Maximum and Mean data values. List below and
then find the z-score for each.
Data Value, x z-score ( z= x?´x
)
s Minimum
Maximum
Mean E. How do -scores indicate a data value is above the mean? _______________________.
z
below the mean? _________________________.
What -score always corresponds to the mean? ___________________________.
z
1 MATH 131
Lab 3 8/16 (2 Points) F. Use Chebychev's Theorem to write a statement about the interval from 2 standard deviations
below the mean to 2 standard deviations above the mean. List the specific interval you used for
your data. Interpret the result in the context of your data. Part 2: V3, Quantitative Data
(3 Points)
A. What is the name of your V3 variable? ________________________________
B. Fill in the values in the chart below using the frequency distribution in Lab 2, Part 3. You may not
need all of the rows below.
C. Use the appropriate values in the table to find the mean for your grouped data.
Remember Data Groups,
using V3 ? (x ? f )
´x = Frequenc
y f Class
Midpoint n x ? f =n
D. Use StatCrunch or Minitab to find the mean and standard deviation of the raw data.
(from Lab 1).
E. Compare the answers in C and D. What accounts for any difference? StatCrunch directions Minitab directions 1. Stat
2. Summary stats
3. Columns 1. Stat
2. Basic Stat
3. Display descriptive statistics 2 x?f ? (x?f ) MATH 131
Lab 3 8/16 3 