## What is the point estimate and 95% confidence interval for the mean improvement in the Kujala score for each treatment group.

Read the paper by Kettunen et al. [14] on the effect of arthroscopy in patients with chronic patellofemoral pain syndrome. (This paper is available online at http://www.biomedcentral.com/1741-7015/5/38.)

(a) What is the point estimate and 95% confidence interval for the mean improvement in the Kujala score for each treatment group.

(b) Was the difference between the two group in terms of mean improvement in the Kujala score statistically significant?

(c) Based on the results published in this paper, create a contingency table, where the row variable is the treatment group, and the column variable is an indicator that is equal to 1 if the patient reports at least moderate improvement at the end of follow-up period and 0 otherwise. Investigate the relationship between the type of treatment and reporting at least moderate improvement.

### Determine the outlet concentration x1 in the water solution and in the trichloroethane solution using an analytical equation.

Predicting Extraction for an Existing Tower with a Given Number of Steps. An existing tower contains 5.0 theoretical steps. It is desired to predict its performance under the following conditions….

### Calculate the minimum solvent that can be used. [Hint: In this case, the tie line through the feed L0 represents the condition for minimum solvent flow rate.

Minimum Solvent and Countercurrent Extraction of Acetone. An aqueous feed solution of 1000 kg/h containing 23.5 wt % acetone and 76.5 wt % water is being extracted in a countercurrent….

### Determine the break-point time, the fraction of total capacity used up to the break point, the length of the unused bed, and the saturation loading capacity of the solid.

Drying of Nitrogen and Scale-Up of a Column. Using molecular sieves, water vapor was removed from nitrogen gas in a packed bed (C1) at 28.3°C. The column height was 0.268….