Math destroyer test 12 Number 3 What is the null hypothesis?

[510586]

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In number 3 of destroyer test 12, it says that Acme claims their thermostat triggers a TCD if the room temperature varies by 1 degree from a constant 70 degrees. 3.2% of the thermostats triggered the room.
If 3.2% of the thermostats were found to trigger the room, why would we reject Acme's claim at a 5% significance level? I'm assuming the claim would be that the thermostats would work. So would 3.2% working be less than the 5% that are claimed to work?

 

[alexis2010]

No. We reject the claim at 5% because the P-value ( 3.2%) is less than the significance level. Remember if P value less than the SL we reject the claim if it's more we fail to reject.

 

[alexis2010]

Also the P value (3.2%) means if more thermostats were tested there's a probability that 3.2% or more will trigger a TCD.

 

[510586]

So is the claim that 5% or more will trigger a TCD?

 

[alexis2010]

No that's not the claim. The claim is that the thermostat will trigger a TCD if the room temperature varies by 1 degree. 5% is the significance level which means that Acme is 95% sure of their claim.

 

[510586]

Ohh OK cool thanks I think I get it now. Destroyer 11 and 12 were much harder than 1-10