Answer:
Sample size should be atleast 617
Step-by-step explanation:
given that a 95% confidence interval for the mean of a population is to be constructed and must be accurate to within 0.3 unit.
i.e. margin of error <0.3
Std devition sample = 3.8
For 95% assuming sample size large we can use z critical value
Z critical = 1.96
we have
Sample size should be atleast 617 to get an accurate margin of error 0.3
Answer:
0.5
Step-by-step explanation:
Solution:-
- The sample mean before treatment, μ1 = 46
- The sample mean after treatment, μ2 = 48
- The sample standard deviation σ = √16 = 4
- For the independent samples T-test, Cohen's d is determined by calculating the mean difference between your two groups, and then dividing the result by the pooled standard deviation.
Cohen's d =
- Where, the pooled standard deviation (sd_pooled) is calculated using the formula:
- Assuming that population standard deviation and sample standard deviation are same:
SD_1 = SD_2 = σ = 4
- Then,
- The cohen's d can now be evaliated:
Cohen's d =