I'd like to briefly introduce myself. Math (and all things number related) have been a huge struggle for me my entire life. Simple things like phone numbers and street address get so jumbled up in my mind (and the street signs and piece of paper on which they're written) that I'm lost more often than not. My difficulties with math (and the resulting phobia) goes all the way back to 2nd grade when I used to get physically ill every day during the math period. I am old enough that algebra was not a required subject in high school, so of course I never made the attempt, and got no further than general math where I struggled through the basics of addition, subtraction, multiplication and division.

Having said all that, I have recently returned to school after a 30 year absence. I'm doing fairly well in most of my studies with the exception of - you guessed it - the math classes. I'm sure I sounded like a complete idiot the first day of pre-al when I asked why there were letters in math problem. LOL. At any rate, with a great deal of time (6-8 hours a day) and hard work I have made it as far as Statistics. I apologize for rambling about issues not pertinent to the math problem, but I figured if you knew my back round you might better understand that I need information broken down to a very basic level. So here we go...

This is the problem I'm currently struggling with:

"An experiment was conducted to compare the efficacies of two drugs in the prevention of tapeworms in the stomachs of a new breed of sheep. Samples of size 5 and 8 from each breed were given the drug and the two sample means were 28.6 and 40.0 worms/sheep. From previous studies, it is known that the variances in the two groups are 198 and 232, respectively, and that the number of worms in the stomachs has an approximate normal distribution. A 95% confidence interval for the the difference in the mean number of worms per sheep is?"

I know that the answer is supposed to be 11.4 +/- 16.2 but I have no idea how it was found. We are using a calculator for almost all of our work at this point and I've spent

*days*punching numbers and have yet to find the correct sequence. I'm beginning to think there's a wicked 'trick' to this question that I'm not seeing. I was so sure that I should use 2-SampTInterval. I used n1 = 5, xbar1 = 28.6, Sx1 = 198, n2 = 8, xbar2 = 40, Sx2 = 232. Today I've sat and gone over the wording and now wonder if I'm using the wrong numbers. The problem says that we are comparing 2 different drugs on

*a new breed of sheep*, but then it says we have samples from

*each breed*. So are we comparing the 2 different drugs or are we comparing 2 different breeds? And if the sample sizes are only 5 and 8, how can the means be 28.6 and 40? I'm definitely not reading something right.

And as an aside (but probably equally important), in class when when worked these problems our answers didn't finish this way. All our instructor had us write was (this number) < mu1 - mu2 < (this number). That was the final answer. I assume the + / - 16.2 is the margin of error, but where does the 11.4 come from?

Again I apologize for rambling. I guess I just wanted to be clear that I'm not just looking for an easy answer to my homework...i am truly putting in the time and still struggling mightily.

Thanks,

La