Sample Proportions
The symbol used for Proportions
p̂
The symbol used for the POPULATION mean
μ
t*
A small part to represent the entire population
Sample
The sampling distribution can be approximated by this
The 3 conditions used
1. Simple Random Sample
2. 10% Rule
3. Normal Distribution
The Point Estimate for a Proportion confidence interval
p̂
A number that describes the population
Parameter
The 3 conditions used
1. Simple Random Sample
2. 10% rule
3. Normal Distribution
Equation to find the σ(x̄)
σ(x̄)=σ/√n
How to find the degrees of freedom
n-1
A number that describes the sample
Statistic
The equations used for the Normal Distributions condition
10≤np
10≤n(1-p)
If the population is skewed, how do you confirm the sampling distribution is approximately normal?
By CLT, (n≥30)
How you can show a Mean distribution is normal if not stated in problem or CLT
Graph a box plot of the data
Our best guess to estimate the population parameter
Point Estimate
As n increases, how does the standard deviation of p̂?
The standard deviation of p̂ decreases
How many times larger must your sample size be to cut the standard deviation of the distribution in half?
4 times as large
With a higher confidence level, how the interval is affected
A wider interval
How close we think we are based on the variability of the sample
Margin of Error