statistics
posted by RAJESH .
drawer contains 50 bolts and 150 nuts. Half of the bolts and half of the nuts are rusted. If one item is chosen at random, what is the probability that it is rusted or a bolt ? In a study to test whether there is a difference between the average height of adult females born in two different
countries, random samples yielded the following results :
n1 = 12O, X1 = 62.7 , S1 = 2.50
n2: 150, X2 : 61.8 , S2 = 2.62
where the measurements are in inches. Use 0.05 level of significance to test the difference between tire average heights.

First question: onehalf = 50%
"X" is typically used to stand for a raw score. If you don't have the symbol, you can write out "mean."
Z = (μ1  μ2)/Standard error of difference between means (SEμμ)
SEμμ = √(SEμ1^2 + SEμ2^2)
SEμ = SD/√(n1)
You are looking for z > 1.96 to reject Ho at .05 level.
I'll let you do the calculations.
Respond to this Question
Similar Questions

Chemistry
Assume that you had 15 nuts (N) and 10 bolts (B). How many N2B molecules could you make by screwing two nuts onto each bolt? 
MATH
4. 8 bolts and 6 nuts weigh 138 grams. 3 bolts and 5 nuts weigh 71 grams. Work out the weight of the following: (a) 4 bolts and 3 nuts (b) 11 bolts and 11 nuts (c) 3 bolts and 3 nuts (d) 1 bolt 
statistics
A bag cntains 100 bolts nd 300 nuts 50% f each hv been rusted 1 item z chosen at random. Find da probability dat chosen item z rusted or a bolt. 
math
A bag contains 100 bolts and 300 nuts 50% of each have been rusted 1 item is chosen at random. Find the probability that chosen item z rusted or a bolt. 
Chemistry
a.) Assume that you had 100 nuts (N) and 75 bolts (B). How many NB molecules could you make by screwing one nut onto each bolt? 
chemistry
a new compound composed of just HexNuts and bolts is formed.A 13.7 Kg sample of the new compound is separated into its component elements with the following result 3.84 kg. of hexnuts and 9.90 kg of bolts. 1. How many hexnuts are … 
chem
a new compound composed of just HexNuts and bolts is formed.A 13.7 Kg sample of the new compound is separated into its component elements with the following result 3.84 kg. of hexnuts and 9.90 kg of bolts. 1. How many hexnuts are … 
statistics
please help me on this; In the mass production of bolts it is found that 5% are defective. Bolts are selected at random and put into packets of ten. A packet is selected at random. Find the probability that it contains: A. no defective … 
STATISTICS
In the mass production of bolts it is found that 5% are defective. Bolts selected at random and put into packets of ten. A packet is selected at random. Find the probability that it contains (a) three defective bolts. (b) less than … 
Statistics
3 bolts and 3 nuts are in a box. 2 parts are chosen at random. Find the probability that 1 is a bolt and 1 is a nut.