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Confidence interval with Z
A 95% confidence interval for the population mean can be calculated using a sample of 20 observations from a normal population with known variance of 20. The sample mean was 40. The confidence interval is calculated as the sample mean (40) plus or minus the critical value of z (1.96 for 95% confidence) multiplied by the standard error. So the 95% confidence interval is 40 ± 1.96(√20/√20) = 40 ± 4.47 = [35.53, 44.47].
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Confidence interval with Z
- 1. INTRODUCTION Name: Habiba Rollno: 250 Topic Confidence interval with “ Z”
- 2. Confidence interval Itis a range of values that defined as specific probability that the values of parameter lies within it. OR Estimation of population parameter using observed sample data.
- 4. GRAPH FOR ZINTERVAL:
- 5. Confidence interval withZ Confidence interval when “Standard deviation” is known it is known as confidence interval with Z. For a population with unknown mean and known standard deviation , a confidence interval for the population mean , based on a simple random sample (SRS) of size n, is + z* , where z* is the upper (1-C)/2 critical value for the standard normal distribution .
- 6. What is (1-C)? It is known as “LEVEL OF CONFIDENCE” Probability of not committing type 1 error is known as level of confidence & denoted by 1-C).
- 7.
- 8. FOR EXAMPLE. A randomsample of 20 observations was drawn from a population, whose variance is 20, had a sample mean of 40, compute a 95% confidence interval for ?