Recent content by markosheehan

So the forumula is x-u/(s/✓n). Where X is the value 101.6 U is the mean which is 100,s is the standard deviation which is 15 , n is the size of the sample which is what we are looking for. What I'm not sure is what I am supposed to equal this to. I know it's something to do with the 5% level...

i am stuck on question 12 I am trying to use the hypothesis testing 1 sample t test formula . the right answer is 338 but I can not get this

thanks

519, 581 is the answer at the back of the book. Usually we use the margin of error formula E=1/✓n We have also used the margin of error (for c% confidence interval) E=z* standard deviation of proportion where z is 1.96 at the 95 % confidence. I'm not too sure how this formula works or what...

a radio station claims 55% of all listeners tune into their program between 8 and 9 am. To check this claim a competing radio station does a survey of a random sample of listeners in the 8 to 9 am time slot. the survey indicates the claim can not be rejected. if the sample size is 1000 people...

thanks I do not see how they can just resolve forces at point c horizontally and vertically. For these type of questions I was always told you can only resolve forces horizontally and vertically for the whole system not just 1 random point on the system. can you just resolve forces...

could someone please explain to me why there is no relative force at point a where the rod ab is attached to a thanks

thanks

thanks for your help how did you know "Since K is very soluble, the precipitate must be from Mg." is it just a general rule you just learn off that potassium is more soluble than mg. just because k is more soluble than mg how did you know mg would join with the (co3)^2- thanks

can someone help me with the 1989 question. i think part i is k2(c03) for ii the gas given of is co2. 1 one the precipitates given off was caco3. i am not sure what the other was. is it supposed to be a reaction between mgso4 +k2co3?

its to do with the hydrogen bonding . thanks

Why does cyclohexane float on water.? When I add up their relative molecular masses water has a lower value than cyclohexane?

Thanks . Ok so only divide when you are dealing with grams of a substance in a solution to find out the number of grams in that amount of solution.

in the vinegar titration they ask for the the concentration of the ethanoic acid in the original vinegar so if you get your answer in grams per liter. so would be not have to take into this consideration by dividing by 10 to find the amount of grams in the original solution.

anyone?