## CI Calculator for difference between means-examples

Confidence interval calculator for difference of means Use this calculator to determine the confidence interval for difference between means when variances are known. Confidence Interval Calculator for Difference of means   Sample 1 Sample 2 Sample Mean Sample Size Population Standard Deviation Confidence Level ($1-\alpha$) Select90%95%98%99% Calculate Results Standard Error of Diff. of Means: Z-critical …

## Confidence interval for ratio of variances

Confidence Interval for ratio of variances Let $X_1, X_2, \cdots , X_{n_1}$ be a random sample of size $n_1$ from $N(\mu_1, \sigma_1^2)$ and $Y_1, Y_2, \cdots , Y_{n_2}$ be a random sample of size $n_2$ from $N(\mu_2, \sigma_2^2)$. Moreover, $X$ and $Y$ are independently distributed. $100(1-\alpha)$% confidence interval estimate of ratio of variances is  …

## Confidence Interval for ratio of variances Examples

Confidence Interval for ratio of variances In this tutorial we will discuss some examples on confidence interval for ratio of variances. Example 1 The same capacity of hard drive is manufactured on two different machines, Machine A and Machine B. Samples are taken from both machines and sample mean manufacturing times and sample variances are …

## Confidence Interval for means when variances are known

In this article we will discuss about the theory of confidence interval for difference between two means when population standard deviations are knonw along with the step by step procedure to construct a confidence interval for difference between two population means when the population standard deviations are known. CI for difference between two means when …

## Confidence interval for two proportions examples

Confidence interval for two proportions examples In this tutorial we will discuss some examples on confidence interval for difference between two population proportions. Example 1 A random sample of 85 parts manufactured by machine A yields 10 defective and a random sample of 110 parts manufactured by machine B shows 28 defective. Compute 95% confidence …

## Confidence interval for two proportions

Confidence interval for two proportions Let $X_1$ be the observed number of individuals possessing certain attributes (number of successes) in a random sample of size $n_1$ from a large population with population proportion $p_1$ and let $X_2$ be the observed number of individuals possessing certain attributes (number of successes) in a random sample of size …

## Plus Four Confidence Interval for Proportion examples

Plus Four Confidence Interval for Proportion Examples In this article we will discuss step by step examples to construct a plus four confidence interval for population proportion. Example 1 In a random sample of 60 students from a college, 32 opted mathematics as major subject. Using plus four method find a 95% confidence interval for …

## Plus Four Confidence Interval for Proportion

Introduction In this article we will discuss step by step procedure to construct a plus four confidence interval for population proportion. The plus four confidence interval for the population proportion can be used when the confidence coefficient is more than 90% and the sample size of the population is at least 10. Plus Four Confidence …

## Confidence Interval for Variance Examples

Confidence Interval for Variance with Examples In this tutorial we will discuss some numerical examples to understand how to construct a confidence interval for population variance or population standard deviation. Example 1 The mean replacement time for a random sample of 12 microwaves is 8.6 years with a standard deviation of 3.6 years. Construct a …

## Confidence Interval for mean sigma unknown

Introduction Confidence interval can be used to estimate the population parameter with the help of an interval with some degree of confidence. One such a parameter that can be estimated is a population mean. In this article we will discuss step by step procedure to construct a confidence interval for population mean when the population …