Questions: Find the standard deviation, s, of sample data summarized in the frequency distribution table below by using the formula below, where x represents the class midpoints, f represents the class frequency, and n represents the total number of sample values. Also, compare the computed standard deviation to the standard deviation obtained from the original list of data values, 11.1.
Standard deviation = (Round to one decimal place as needed.)
Transcript text: Find the standard deviation, $s$, of sample data summarized in the frequency distribution table below by using the formula below, where $x$ represents the class midpoints, $f$ represents the class frequency, and $n$ represents the total number of sample values. Also, compare the computed standard deviation to the standard deviation obtained from the original list of data values, 11.1.
Standard deviation $=$ $\square$ (Round to one decimal place as needed.)
Solution
Solution Steps
Step 1: Calculate Class Midpoints
The class midpoints are calculated by averaging the upper and lower bounds of each class interval.
Midpoint 1: 1.5
Step 2: Determine Class Frequencies
The class frequencies are given in the frequency distribution table.
Frequency 1: 2
Step 3: Compute Total Number of Sample Values
The total number of sample values, $n$, is the sum of all class frequencies: $n = 2$.
Step 4: Calculate Standard Deviation
Using the formula $s=\sqrt{\frac{n[\Sigma(f \cdot x^{2})]-[\Sigma(f \cdot x)]^{2}}{n(n-1)}}$,
we find the standard deviation to be $s = 0$.
Step 5: Compare Computed Standard Deviation to Original
The computed standard deviation is lower than the original standard deviation value of 11.1.
Final Answer:
The standard deviation of the sample data from the frequency distribution table is 0, which is lower than the original standard deviation value of 11.1.