homework help

  1. J

    R homework

    1. Fit appropriate regression models to describe relationship between the variables X and Y using the following three data sets separately. Use Y as the response and X as the explanatory variable. You must show all the necessary tables and fi gures for the model fi t and also comment on the fi...
  2. C

    Homework Problem. Please Help!

    I'm having problems mostly with part (b) and (c). Please add every single step and side note you can - including formulas used. I greatly appreciate the help! A company purchases large shipments of lemons and uses this acceptance smaplong plan: randomly select and test 200 lemons, than accept...
  3. T

    Normal Approximation to the Binomial Distribution Help Needed

    SOLVED - Normal Approximation to the Binomial Distribution Help Needed A multiple choice test consists of a series of questions, each with four possible choices. a) If there are 60 questions, estimate the probability that a student guessing blindly on each question will get at least 30 right...
  4. K

    permutations and confidence intervals

    Hello! I am in need of a little guidance on a stat problem... I've performed a permutation on two data sets, in R, regarding sunblock efficacy, and have concluded that in any permutation, there is only one instance of matching efficacy, the original data set. now I have to find a 95% C.I...
  5. S

    confidence interval with R

    I am trying to predict the amount that a male with average status, income and verbal score would spend along with an appropriate 95% CI. I used my linear model with all my variables and sex is coded as male=0 and female=1 in data set. I think I did something wrong because I get all 47...
  6. L

    Descriptive Summations

    How would I go about solving this? 1/nΣxi^2=100 and 1/nΣxi=2. Define yi=2xi+1 and find 1/nΣyi^2.
  7. Y

    A random variable that is a mix of discrete and continuous

    Here's a question we got for homework: It is given that at a certain bank there's 50-50 chance that when you enter there's: - no one waiting in line - there's one man waiting, in which case the waiting time is exponentially distributed. What is the CDF of the total waiting...
  8. M

    sum of independant poisson processes help

    HI, I've a question that says accidents to people and animals are independant poisson processes with intensity lambda and mu respectively. I'm asked given that the total amount of accident last year was 4, what is the distribution of no. of accidents to people? I'm not quite sure how to approach...
  9. M

    poisson processes help

    Hi, i'm stuck on a basic poisson process question. If Xt (where t is a subscript) is a poisson process with intensity lambda what is the conditional distribution of Xt1 = N(0,t1] for t>t1? I think N(0,t1] denotes the number of arrivals from 0 to t1. Helpwould be appreciated as I don't even know...
  10. F

    Suppose there's two events, A & B, with P(A)=75% and P(B)=66%. Select all that apply

    Hello, I'm having a lot of trouble with this homework question and I really need help figuring it out! Suppose there are threeevents, A, B, and C, with P(A)=70%, P(B)=20%, and P(C)=10%. Select all that must apply. 1. If B implies A, P(A U B U C) is less than or equal to 80 percent 2. A cannot...
  11. N

    Homework help - calculating ρ

    Hi everyone, I'm new to the forum and I would really appreciate some help with a homework problem. Sorry about possible language mistakes, my native language is Swedish... Here is my problem: Let Y=Z-3X^2 where X and Z are normally distributed N(0,1). Simulate n=50 observations of (X,Y) and...
  12. U

    Mean Squared Error

    i've been attempting a question on mean square error and find it impossible to do so I was looking for some help. It's quite a long question here it is: Suppose a tv company wishes to estimate proportion of homes with at least 2 televisions. Suppose in fact unbeknown to the tv company the...
  13. B

    Hypothesis Testing Homework

    Please help, I don't know where to start with this question. A large manufacturing company found that in the past 32% of all supply shipments were received late. A new system was recently implemented. A random sample of 118 deliveries since the system was installed revealed that 22 deliveries...