Question

You would like to compare the effectiveness of the three types of steroid therapies (S1, S2, S3) in combination with anti-viral drug therapies (D1, D2, D3) for COVID-19 positive patients. You compare therapies by the number of days it takes to test negative (recovery time). Determine if there is a significant difference in recovery time due to the steroid therapy, anti-viral drug therapy type, or the interaction between the two with 90% confidence. Create a bar graph, box-and-whisker plot, or similar graph that compares mean and standard deviation (error bars) of your groups (don’t forget to label your axes).

*please let me know which test to use

Answer 1

Since there are two types of therapies

1. steroid therapies
2. anti-viral drug therapies

Now, these two therapies will be our treatments whose effect we have to determine.

Here both of these therapies have 3 levels which are combined with 3 separate levels of another factor.

Now, these levels are categorical variables and

Variable of interest i.e. number of days it takes to test negative (recovery time) is continuous.

Two way ANOVA would be appropriate for this study.