[The following information applies to the questions displayed below.] The director of cost management for Odessa Company uses a statistical control chart to help management determine when to investigate variances. The critical value is 1 standard deviation. The company incurred the following direct-labor efficiency variances during the first six months of the current year. The standard direct-labor cost during each of these months was $19,000. The controller has estimated that the firm's monthly direct-labor variances have a standard deviation of $950. Required: 1-a. Draw a statistical control chart and plot the variance data given above. 1.b. Which variances will be investigated