hypothesis testing

  1. S

    Hypothesis Testing Confusion with Significance Levels

    I need help in setting both of these up. I am confused on how to do significance levels in my problems. We are currently studying Hypothesis Testing and sorts. TIA! 20)In December 2001, 38% of adults with children under the age of 18 reported that their family ate dinner together 7 nights...
  2. K

    model comparisons for a binomial distribution

    Dear all, I have a stats question that relates to a bigger piece of research, but I've simplified the bit I'm confused about... Suppose I run an experiment 10 times (M=10) where for each experiment I toss a coin 20 times (n=20), I have for each experiment the number of heads (x). From this...
  3. B

    A regression problem with optional treatment

    I have an interesting problem here and really need your suggestion to analyze the data in a proper way. In 2012 we collected data about retention of the students from first semester to second semester along with some other variables. The retention variable is a binary type variable-...
  4. C

    Writing null hypothesis and deciding on rejection criteria

    The number of faults in one metre of a thread is Poisson distributed.It is claimed that the average number of faults is 0.02 per metre.A random sample of 100 one metre lengths of the thread reveals a total of 6 faults.Does this information support the claim? What I want to know whether my H0...
  5. S

    It should be s simple answer about Hypothesis Testing!

    Hi, I am trying to understand from seeing in sites, hear this site explains it good Please have a look hear. Somewhere it says: "The z-score that corresponds to .05 is -1.645" (you may press ctrl+F4 to find it quickly). How did he find that z of 0.05 is -1.654 in the table of z-scores I, I...
  6. V

    Hypothesis Testing

    You arrive late at a race track; the cars are already hurtling past you. You know from past experience that the cars are numbered (and labeled) 1, 2, 3, …, up to STAT 2003 Computer-Aided Statistical Reasoning 1-20 N, the total number of cars in the race. Unfortunately, N is unknown to you...
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    Calculating the size of Type 1 error, Type 2 error and power of the test

    Let X have a binomial distribution with parameter n=5 and P\in [p:p=\frac{1}{4},\frac{1}{2}]. The null hypothesis H_{0}:P=\frac{1}{4} is rejected, and The alternative hypothesis H_a:P=\frac{1}{2} is accepted. If the observed value of X_1, a random sample of size one, is less than or equal...
  8. R

    Why not go with tests dealing with unequal variances/unbalanced sample size first?

    Hi All, Here is the context: a lot of texts for hypothesis testing/ANOVA first examine the cases where either the number of samples per group are the same (n1 = n2 = n3 = ...= nn) or the variances for each group are comparable (s1 = s2 = s3 =... = sn). And a lot of times, I see "Conduct the...
  9. S

    Hypothesis Testing for Standard Deviation

    Hello! Attempting to complete this problem: -- The observations (volume in m^3/ha) of 10 prism plots from a given forest type are summarized as follows: sample mean = 420 m^3/ha "10" on top of the ∑ and "i-1" below the sigma, with "x^2" beside it = 1,778,400 (m^3/ha)^2 Using the...
  10. M

    Estimating Covariate Effects on Likert-Scale Response Data

    I am working on a problem where we elicit medical residents perceptions regarding the importance of specific core medical competencies (professionalism, collaboration, medical expertise, etc.) on a 5 point Likert scale. For example, "In your current residency role how important is...
  11. D

    Testing data to determine proficiency.

    Hi, I have been giving a work project and I believe that I need to use t-tests to get to my results, but don't know what results I need to get to determine how long it takes our new hire employees to reach proficiency. I have 3 separate data sets (approx 70,000 lines of excel data) which...
  12. M

    Comparing results presented as percents. Best method

    Hi folks, I was wondering if you could help me wrap my head around the best way to present some data and the best statistical test to use to illustrate a comparison. Here is the breakdown: Group A (N=41) was asked to complete a questionnaire that asked them specific questions on a topic...
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    test difference in marginal effects for a dummy variable, different computations

    Dear Talk Stats readers, I have a Stata problem. I would like to test whether the difference between the marginal effects of a dummy varaible, obtained first by computing the difference and then by taking the derivative, is statistically significant. I want to implement this test in order...
  14. D

    Which test for comparing before/after and control groups?

    Not sure which hypothesis tests would be best in these three scenarios: 1. Compare Before & After Scores Students take a course, with a pre-test and a post-test. Is the course effective? e.g.: ...............People..Pre-test Avg..Post-test Avg Population 1....30.........72%...........78%...
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    Hypothesis testing of two data series

    Hi, I am new to this forum. :wave: I have a basic understanding of statistics from a module at university. I am currently pursuing research in management, but I have a serious problem with selecting the right statistical method. I would be very grateful if somebody could suggest me the right...
  16. S

    Hypothesis Testing

    I was asked a valid question that I couldn't answer. Why perform Hypothesis Testing when I have the entire population data?
  17. K

    Hypothesis tests applied to two means (two related samples) question about null.

    Hello, I am currently studying for an midterm, and am running into a roadblock with some of the concepts concerning hypothesis testing applied to means with two related samples. I am noticing in all of the examples in the textbook that the null hypothesis (mu) is always Ho = 0. Why is it that...
  18. G

    Hypothesis Testing - finding the power and beta!

    A medicine dispensing machine is designed to discharge on average at least 8ml of medicine per dose with a standard deviation of 0.2ml. The amount of medicine per dose is normally distributed. a) If you select a random sample of 16 doses and you are willing to have an (alpha or significance...
  19. J

    Hypothesis Testing

    Hi all, I've got an MCQ question for uni that I'm not sure how to go about :confused:. If anyone could point me in the right direction that would be fantastic. "A university administrator believes that less than 40% of full-time staff regularly use public transport to travel to the...
  20. 1

    Multiple Regression Analysis Issue

    Hi everyone I have just signed up! I am currently doing a thesis & struggling with my regression model. I am examining the link between profit levels debt levels in the oil and gas industry. My Dependent variable is Profitability, Independent variables are Debt/Size of company/Growth rate of...