Math Problem Statement

For a data set of the pulse rates for a sample of adult​ females, the lowest pulse rate is

3636

beats per​ minute, the mean of the listed pulse rates is

x overbarxequals=79.079.0

beats per​ minute, and their standard deviation is

sequals=27.227.2

beats per minute.

a. What is the difference between the pulse rate of

3636

beats per minute and the mean pulse rate of the​ females?

b. How many standard deviations is that​ [the difference found in part​ (a)]?

c. Convert the pulse rate of

3636

beats per minutes to a z score.

d. If we consider pulse rates that convert to z scores between

minus−2

and 2 to be neither significantly low nor significantly​ high, is the pulse rate of

3636

beats per minute​ significant?

Solution

Let's break down the problem step by step.

We have the following dataLet's break down the problem step by step.

We have the following

  • Lowest pulse rate: 3636 beats per minute
  • Mean pulse rate x=79.0\overline{x} = 79.0 beats per minute
  • Standard deviation s=27.2s = 27.2 beats per minute

Part a. Difference between the pulse rate of 36 and the mean pulse rate

The difference can be calculated as: Difference=x36\text{Difference} = \overline{x} - 36 Substitute the values: Difference=79.036=43.0\text{Difference} = 79.0 - 36 = 43.0 So, the difference between the pulse rate of 36 beats per minute and the mean pulse rate is 43.0 beats per minute.


Part b. How many standard deviations is the difference?

The number of standard deviations is found by dividing the difference by the standard deviation ss: Number of standard deviations=Differences\text{Number of standard deviations} = \frac{\text{Difference}}{s} Substitute the values: Number of standard deviations=43.027.21.58\text{Number of standard deviations} = \frac{43.0}{27.2} \approx 1.58 So, the difference is approximately 1.58 standard deviations.


Part c. Convert the pulse rate of 36 beats per minute to a z-score

The formula for the z-score is: z=xxsz = \frac{x - \overline{x}}{s} where x=36x = 36, x=79.0\overline{x} = 79.0, and s=27.2s = 27.2. Substitute the values: z=3679.027.2=43.027.21.58z = \frac{36 - 79.0}{27.2} = \frac{-43.0}{27.2} \approx -1.58 So, the z-score for a pulse rate of 36 beats per minute is approximately -1.58.


Part d. Is the pulse rate of 36 significant?

We are given that pulse rates with z-scores between 2-2 and 22 are considered neither significantly low nor high. Since the z-score for 36 beats per minute is 1.58-1.58, which lies between 2-2 and 22, the pulse rate is not significant.


Let me know if you need any further details!

Here are 5 related questions for deeper exploration:

  1. What does a z-score represent in statistics, and why is it useful?
  2. How would the interpretation change if the standard deviation were much smaller or larger?
  3. What does it mean for a value to be "significantly low" in terms of z-scores?
  4. How do outliers affect the mean and standard deviation of a data set?
  5. Can we conclude anything about the distribution of pulse rates from this sample?

Tip: The z-score can help determine how far away a value is from the mean, making it a key tool for identifying outliers or significant values in a data set.

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Math Problem Analysis

Mathematical Concepts

Statistics
Z-Scores
Standard Deviation
Mean

Formulas

Difference = Mean - Pulse rate
Number of standard deviations = Difference / Standard deviation
Z-score = (Pulse rate - Mean) / Standard deviation

Theorems

Z-score calculation
Standard deviation interpretation

Suitable Grade Level

Grades 9-12