"Chi-Square may not be a valid test'. What other test can I carry out?

Question

I ran a chi-test which gave the following warning with the results i.e. "45% of the cells have expected counts lessthan 5. Chi-Square may not be a valid test". What test can I run.

Answer 1

for a two-way table, you can use fisher's exact test. there are tables for it in some nonparametric statistics texts and some software (such as SAS, SPSS or StatXact) can carry it out too.

if you have a one-way table (as when doing goodness-of-fit), one way to get round the small expectations issue is to pool cells to increase the expectations in the sparser cells. you can then use chi-squared with a smaller degrees of freedom.

Answer 2

That's a tough one without seeing the data and knowing how those data were obtained. Since you ran a Chi Square, I presume you have some expected outcomes versus actual (data) outcomes.

What were the expected outcomes based on...some presumed distribution and associated probability? If so, as one answerer suggested, why not use that distribution for an appropriate parametric statistical test? While most data are Normal distributions, some, like service line arrivals etc., are not. So, without knowing your data, I can only suggest that assuming a Normal distribution should work for most of the data most of the time.

Answer 3

Evelyn is right here, and so is your mechanic and his boss. as quickly as you have a valid MoT certificates it continues to be valid till expiry, it may in actuality be revoked by ability of VOSA yet purely by ability of them. Any next try failure does no invalidate it. this might properly be a thoroughly separate difficulty from that of roadworthiness, which persons look no longer able to allure to close. The MoT would not assure roadworthiness, in actuality they make that perfectly sparkling; it purely confirms that on the time of the try the automobile met all the try standards. you will possibly desire to tension out of the try centre with a sparkling try purely to have a brake mild fail, to illustrate, a remember of yards down the line. the automobile then will become unroadworthy, nonetheless it nevertheless possesses a valid MoT.

Answer 4

TWO-WAY ANALYSIS OF VARIANCE