Math Problem Statement
A variable has a mean of 100 and a standard deviation of 6. Four observations of this variable have a mean of 119 and a sample standard deviation of 8. z= , t =
Solution
To calculate the z-score and t-score, we need to clarify which of the two sets of data you're referencing.
1. Z-Score:
The z-score measures how many standard deviations an observation is from the population mean. It is used when the population standard deviation is known.
The formula for the z-score is:
Where:
- is the sample mean
- is the population mean
- is the population standard deviation
In your case:
- (sample mean)
- (population mean)
- (population standard deviation)
Substitute the values:
So, the z-score is approximately 3.17.
2. T-Score:
The t-score is used when the population standard deviation is unknown, and we only have the sample standard deviation. It is computed using:
Where:
- (sample mean)
- (population mean)
- (sample standard deviation)
- (sample size)
Now substitute the values:
So, the t-score is 4.75.
Summary:
- z-score:
- t-score:
Let me know if you'd like more details or have any further questions!
5 related questions:
- What is the difference between a z-score and a t-score?
- When should you use a t-distribution instead of a normal distribution?
- How does sample size affect the t-distribution?
- What happens to the t-score if the sample size increases?
- Can we use a z-score when the population standard deviation is unknown?
Tip:
For small sample sizes (typically ), use the t-distribution since it accounts for more uncertainty in estimating the population parameters.
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Math Problem Analysis
Mathematical Concepts
Statistics
Z-Score
T-Score
Normal Distribution
T-Distribution
Formulas
z = (X - μ) / σ
t = (X - μ) / (s / √n)
Theorems
Central Limit Theorem
Properties of Z-Distribution
Properties of T-Distribution
Suitable Grade Level
Grades 10-12
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