One environmental group did a study of recycling habits in a California communityIt found that 65% of the aluminum cans sold in the area were recycled(Round μ to the nearest integer, σ to 4decimal places.) (a) If 384 cans are sold today, what is the probability that 300 or more will be recycled? (Use 4 decimal places.)(b) Of the 384 cans sold, what is the probability that between 260 and 300 will be recycled? (Use 4 decimal places.)
Is this assuming a binomial approximation to the normal distribution? If son 384 p probof can recycled .65 q probof can not recycled 1 - p .35 mu np (384)(.65) sigma sqrt(npq) sqrt ((384)(.65)(.35)) Once you have this information, you have to adjust the ranges by 1/2 unit (i forgot what this is called) so a) P( x 300) becomes ) (x 300.5) b) P( 260 x 300) becomes P( 260.5 x 299.5) Now find z-scores for these ( z (x - mu) / sigma ), find the area using the chart for area under normal curve and those will be your probabilities.
You can find out about foam insulationIt takes a professional to do but the walls don't all have to come down.
do you have a crawl space or an attic, if so you can use the blow in insulation, they blow this foam and paper mixture into walls between wall studs also if you have crawl space make sure you have insulation under floor of houseand if you have air vents in your foundation, close these off in winter, makes a big differenceand if worse comes to worse apply the plastic to interior windows, the kind you use a blow dryer to apply to fit.
I'm assuming you're in the UK - if not, then this information is pretty useless so here's hoping! Contact Warm Front - they are a government initiative to help people with just your sort of problemsWe got the whole house insulated free of charge and help with putting in a new boiler and radiators, though we did have to contribute to those costsI think the grant is bigger now so it might be worth checking into itYou can probably find out more on the 'net Definitely give it a go and good luck with it all.
We live in an old house too here's just a few things we did: 1) Plastic all windows (the kind that shrinks when you heat it up with a hair dryer.we used a heat gun.much faster!) 2) Put all new weatherstripping on the entry doors 3) Does your attic need new insulation? Ours did but to help curb the initial expense we just bought a few rolls/bats at a timeMuch easier on the checkbook! 4) Put the socket insulators on all electrical sockets on the outside wall5)Caulk between stationary surfaces like the frame around your front door the side of the houseHope some of these ideas help.I feel your pain in regards to heat this winter.it could be a cold one, in the house that is! Propane is spendy!!!
