The following data related to the life (in hours) of 15 random samples of 5 electric bulbs each, drawn at intervals of one hour from a production process:

<img src='./qimages/10347-1a.jpg'>

Draw the X and R charts and comment whether the process is under control. If not, draw the revised charts.

The data given below represent the number of defects noted per 100 metres in a telephone cable

<img src='./qimages/10347-1b.jpg'>

Analyse the data with a suitable chart. Would you conclude that the process is in statistical control? If not, draw the revised chart.

2. The data given below gives the average monthly prices of a commodity for four years:

<img src='./qimages/10347-2.jpg'>

Calculate the seasonal variation indices using moving average method.

Obtain the deseasonalised values.

Estimate the trend line by method of least squares.

Plot the given data and the deseasonalised values.

3. A study was conducted to examine those variables which are thought to be related to the job satisfaction of employees of a non-professional organisation. A random sample of 15 employees is selected and the data are given below:

<img src='./qimages/10347-3.jpg'>

Prepare a matrix plot to get an idea about the relationship among the variables.

Develop a regression model and perform its analysis at level of significance.

Check linearity and normality assumptions for the fitted regression model