Hypothesis testing Definition and 72 Threads

  1. B

    Multivariate hypothesis testing

    How is hypothesis testing performed for multivariate data? Say for simplicity we have two iid draws from a binomial distribution Bin(10,q) with X1=7, X2=8. Under the null hypothesis H0:q=1/2, the individual p-values (as one-tail probabilities) are approximately 0.172 and 0.055 respectively...
  2. D

    Normal Distribution: Hypothesis Testing

    Homework Statement A cola company's long-term market share is estimated to be 45%. After an extensive advertising campaign, 68 out of 150 customers surveyed claimed to have purchased this company's cola recently. Was the advertising campaign a success? justify your assessment Homework...
  3. Q

    Hypothesis Testing: Binomial Experiment

    Homework Statement A drug company markets a medication that cures about 60% of cases with depression. A CB program is thought to be more effective. It was delivered to 15 depressed people. Determine the minimum number of cured people required to support the claim that the CB program is more...
  4. Q

    Hypothesis Testing - Basic Theory Question

    Homework Statement Karen asks John to guess the date of her birth, not including the year (i.e. the day and month she was born; discount leap years). If John guessed correctly on his first try, would you believe his claim that he made a lucky guess or would you be suspicious that he already...
  5. W

    Regression strategy for hypothesis testing vs prediction

    Hi, I'm interested in this question primarily in how it relates to what is usually called classic or frequentist statistics (p-values, etc). I'm fully aware of how stepwise and other automated techniques can negatively impact analyses and render inference based upon parameter estimates...
  6. N

    Hypothesis Testing: Comparing Car Repair Costs with New vs Old Bumper Bars

    Homework Statement A hire-car firm is considering a special bumper bar designed to lower the cost of car repairs following minor accidents. This bumper bar is more expensive than the conventional one. It will only be introduced permanently if any reduction in the cost of repairs is judged to...
  7. W

    Hypothesis Testing in Statistics

    Homework Statement A random sample of 30 rats has 18 females and 12 males. If last year's proportion of females treated was 0.65, do the above data confirm that this year the proportion of females is different than last year? Homework Equations p = treated / total If using standard...
  8. W

    Sensitivity analysis, missing data, and hypothesis testing

    Hi, I have a large data set with with less than 10% missing values (missing response, but all predictor variables present). It is a near certainty that these values are not missing at random, dependent upon the missing value. The response is survival time of a land parcel with 'death' being...
  9. S

    Calculating Probability of Cars' Expected Speed with Hypothesis Testing

    If \sigma = 10 km/h and \mu = 74 km/t, find the probability that we when measuring the speed of 12 random cars can conclude that the expected speed of the cars is less than 77 km/h. Use \alpha=0.05 level of significance. z = \frac{\bar{x}-\mu_0}{\sigma / \sqrt{n}} =...
  10. K

    Hypothesis testing for pairs of means

    Homework Statement 1a) The strength of concrete depends to some extent on the method used for drying it. Two different drying methods were tested independently on specimens. The strength using each of the methods follow a normal distribution with mean μ_x and μ_y respectively and the same...
  11. K

    Hypothesis Testing: Power Function

    Homework Statement http://www.geocities.com/asdfasdf23135/stat14.JPG Homework Equations Statistics: power function The Attempt at a Solution a) Test statistic: Z = (X bar - 13) / (4/sqrt n) Let μ = μ_a > 13 be a particular value in H_a Power(μ_a) = 1- beta(μ_a) = P(reject Ho |...
  12. E

    Hypothesis Testing: Distinguishing Zero vs Practical Equivalence

    What is the difference between NOT being able to reject the hypothesis that a particular parameter is zero and being able to conclude that it is within some acceptable distance from zero ("practical equivalence")? I guess this is more of a logic question, but I'm still having trouble...
  13. M

    Hypothesis Testing Homework: Does Your Relationship Support Claim?

    Homework Statement I have used OLS and found that: b0 = 6,85 b1 = 3,88 with se= 0,1121 n = 20 Person x claims that b1 = 5 Choose an alternative hypothesis. Does your estimated relationship support this claim? Use a 5 % significance level The Attempt at a Solution H0 = b1 =...
  14. C

    Standard deviation and hypothesis testing

    Hi guys. Im new at this site so please be nice to me =P. I've been working on some practice papers for my upcoming end of semester exams. Cant get these two questions out ><. Any help is greatly appreciated Thanks in advance jenny xoxo 1. A sample of 28 students measured their...
  15. D

    What is the Probability of Rejecting the Mean of 130 at the 1% Level?

    Homework Statement Having trouble understanding the question, which is... voltage specified to be 130 Sample of 20 readings gives sample mean of 128.25 Also given s.d.=3. "It is important that the voltage not be allowed to drop below 128 volts. What is the probability of rejecting mean...
  16. C

    Hypothesis Testing: How to Recognize Ho & Ha

    I really don't understand hypothesis testing. How do I recognize which one is Ho and Ha in a problem? Is there a particular trick to facilitate my lfie?
  17. T

    Is a Two-Sided t-Test Appropriate for Comparing Doctor Care Hours?

    Need to know the test that will be performed on the following question: The data comprises hours devoted to patient care per week for practitioners in conventional and alternative medical practices. Question: Can we infer that the mean amount of time devoted to patient care per week by...
  18. A

    How to determine the width of the zone of acceptance in hypothesis testing?

    First and foremost, I am terrible in Stats so bear w/ me on this one. This is my question, if anyone has an idea on how to figure out this problem that would be great! Here it is: Suppose you flip a coin 100 times and you want to test the hypothesis that the coin is fair, making sure there is...
  19. A

    Hypothesis testing and the power of the test

    I am having trouble understanding the concept of the power of the test. Here is a sample question with solution: A company wants to test if average weekly demand is more than 2000 lbs. Test is to be carried out at 5% level of significance, and an estimate of the population variance is...
  20. C

    Hypothesis testing with normal distribution

    Hypothesis testing with normal distribution... I've been learning about Hypothesis testing with normal distribution, but I don't understand the need for the significance level. By this I mean that i understand that according to the Central Limit Theorem a distribution of the means will be a...
  21. S

    Question about hypothesis testing

    i'm getting my concepts very confused now... so the formula for the normal distri is (y - u)/(sigma)/((sqroot(n)). so if I want to test y, I set that formula = to alpha(where alpha is the confidence level). that is if it is one sided. if it is 2 sided, do I still set it to alpha, or...
  22. N

    Hypothesis Testing for NCAA Champion Probability in Big East Conference

    Using a .05 level of sign, test the hyp that the probability of the NCAA champion being from the big east is 20% The actual ratio is 3/63 Where should I start? thanks nautica
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