In: Statistics and Probability
Sharpe Middle School is applying for a grant that will be used to add fitness equipment to the gym. The principal surveyed 16 anonymous students to determine how many minutes a day the students spend exercising. The results from the 16 anonymous students are shown.
0 minutes; 40 minutes; 60 minutes; 30 minutes; 60 minutes; 10 minutes; 45 minutes; 30 minutes; 300 minutes; 90 minutes; 30 minutes; 120 minutes; 60 minutes; 60 minutes; 0 minutes; 20 minutes
** Lp = (p/100) (n + 1) (the p-th percentile formula to get the location).
Determine the following five values.
Min =
Q1 =
Med =
Q3 =
Max =
If you were the principal, would you be justified in purchasing new fitness equipment?
ANSWER:
Is/are there any potential outlier (s)?
IQR=Q3-Q1=………………………………
Lower Limit: Q1 - 1.5(IQR) =……-…………..
Upper Limit: Q3 + 1.5(IQR)=……………..
Calculating the Arithmetic Mean of Grouped Frequency Tables
When only grouped data is available, you do not know the individual data values (we only know intervals and interval frequencies); therefore, you cannot compute an exact mean for the data set. What we must do is estimate the actual mean by calculating the mean of a frequency table. A frequency table is a data representation in which grouped data is displayed along with the corresponding frequencies. To calculate the mean from a grouped frequency table we can apply the basic definition of mean: mean = data sum/number of data values.
We simply need to modify the definition to fit within the restrictions of a frequency table.
Since we do not know the individual data values we can instead find the midpoint of each interval.
The midpoint is = (lower boundary + upper boundary)/2.
We can now modify the mean definition to be
Mean of Frequency Table = Σ f m/Σ f
where f = the frequency of the interval and m = the midpoint of the interval.