z test

  1. M

    Z test: can I use it in this context ?

    Hello all. Nice to meet you. I would like to consult you regarding a problem I'm facing: Imagin you have a dataset containing all of the operating workplaces in a certain city (say, 500 in number). The dataset contains the workplace name, average salary and percentage of workers by race and...
  2. S

    Whether to use z test or t test

    hi team, I got the following question given below. According to me this should be solved using z test as the sample size is more than 30. But they are using t test. What is the correct method z test or t test? Please advice A social worker wants to know whether the mean annual salary of...
  3. K

    Directional test help

    Directional test (H1:M<μ) – In the city there is normally a mean of 75 parking tickets issued per officer with a standard deviation of 12. The police are testing a new no parking signs using a sample area of 30 officers and tickets are down to a mean of 68. Is this significantly lower?
  4. K

    I need help with directional test

    Directional test (H1:M>μ) – You are trying out a new fertilizer on your farm. The population mean for your corn is 130 lbs per acre with a population standard deviation of 20 lbs. Your test sample of 60 acres resulted in 133 lbs per acre. Is this significantly more? The z score i got is...
  5. S

    Chi square and Z test for proportions for nominal data

    I believe that to analyse 2 sets of nominal data chi square test is used ... can't we use Z test for proportions also to analyse 2 sets of nominal data ...
  6. S

    Comparing proportions from the (somewhat) same sample

    Hi everybody, I’m looking for some help on testing whether there are statistical differences between proportions when the data is dependent. By dependent, I mean that all the data is from the same participants though I’m not talking about a repeated measures experimental design but instead...
  7. S

    Which statistical procedure to use (given standard deviations and means)?

    Can someone please help me with this? Which statistical procedure could I use, and how could I set this up? A company operates four machines during three shifts each day. From production records, the data in the table below were collected. At the .05 level of significance test to determine if...
  8. M

    Need urget help for one sample z test of proportions

    Hi All, I need to confirm whether I am doing it correctly. Survey question is: Have you ever witnessed violent episodes/incidents in the last week? 1. NO 2. Yes. 58% witnessed/experienced violent incidents and others 38% didn't with 4% missing responses. I just need to test...