I have an experiment on cancer cell lines.

There are 7 cell lines.

Each cell line is treated with a different concentration of the same drug.

The average concentration that killed half the cells in each cell line is calculated, along with a standard deviation as follows:

Cell Line ////// Avg Conc ////// SD

1 ////// 0.03 ////// 0.00

2 ////// 7.84 ////// 0.50

3 ////// 6.72 ////// 2.86

4 ////// 10.78 ////// 1.56

5 ////// 10.68 ////// 9.07

6 ////// 15.14 ////// 2.87

7 ////// 32.27 ////// 0.35

Question 1

To say that cell line 1's average concentration is statistically smaller than all the others is it best to use an ANOVA comparing across all 7 groups?

Or do I use a t test and compare Cell line 1 to cell line 2.... cell line 1 to cell line 3...etc? My understanding from reading is this is the wrong way to do this because I am bound to find a statistical difference somewhere doing this.

Question 2

I know to use either the t-test or ANOVA I need normally distributed data. Because cell line 5 has a SD that is quite high, do I assume that it is not a normally distributed result and therefore comparing across cell lines, I should use the Kruskal Wallis test instead?

There are 7 cell lines.

Each cell line is treated with a different concentration of the same drug.

The average concentration that killed half the cells in each cell line is calculated, along with a standard deviation as follows:

Cell Line ////// Avg Conc ////// SD

1 ////// 0.03 ////// 0.00

2 ////// 7.84 ////// 0.50

3 ////// 6.72 ////// 2.86

4 ////// 10.78 ////// 1.56

5 ////// 10.68 ////// 9.07

6 ////// 15.14 ////// 2.87

7 ////// 32.27 ////// 0.35

Question 1

To say that cell line 1's average concentration is statistically smaller than all the others is it best to use an ANOVA comparing across all 7 groups?

Or do I use a t test and compare Cell line 1 to cell line 2.... cell line 1 to cell line 3...etc? My understanding from reading is this is the wrong way to do this because I am bound to find a statistical difference somewhere doing this.

Question 2

I know to use either the t-test or ANOVA I need normally distributed data. Because cell line 5 has a SD that is quite high, do I assume that it is not a normally distributed result and therefore comparing across cell lines, I should use the Kruskal Wallis test instead?

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