 ### According to census data in 1950 the population of the US amounted to 151.3 million persons.

This question aims to find the practical and statistical significance of the difference in percentages of two different populations. In the 1950s, the population of the US amounted to 151.3 million persons and 13.4 % of them were living in the West according to census data. This population percentage increased to 281.4 million and 22.5 […]

### For a test of Ho: p=0.5,the z test statistic equals -1.74. Find the p-value for Ha: p<0.5.

The question aims to find out the p-value using the given alternative hypothesis, which is a one-sided hypothesis. Therefore, the p-value will be determined for the left tail test with reference to the standard normal probability table. When the alternative hypothesis states that a certain value for a parameter in the null hypothesis is lesser […]

### Which of the following are true about regression with one predictor variable? Check all the given options.

The regression equation is the line that best fits a set of data as determined by having the least squared error. The slope shows the amount of change in Y for a one-unit increase in X.  After conducting a hypothesis test and the slope of the regression equation is nonzero, you can then conclude that […]

### Suppose that X is a normal random variable with mean 5. If P(X>9)=0.2, approximately what is Var(X)?

This question aims to find the probability of a normally distributed random variable $X$. A random variable is one whose value is determined by the results of a statistical experiment. The normal distribution, also known as the Gaussian distribution or the z-distribution, has a mean of zero and a standard deviation of one. Data in a […]