How to ask a statistics question
To get a good answer, you must write a good question. Answering a statistics question without context is like boxing blindfolded. You might knock your opponent out, or you might break your hand on the ring post.
What goes into a good question?
1. Tell us the PROBLEM you are trying to solve. That is, the substantive problem, not the statistical aspects.
2. Tell us what math and statistics you know. If you’ve had one course in Introductory Stat, then it won’t make sense for us to give you an answer full of mixed model theory and matrix algebra. On the other hand, if you’ve got several courses or lots of experience, then we can assume you know some basics.
3. Tell us what data you have, where it came from, what is missing, how many variables, what are the Dependent Variables (DVs) and Independent Variables (IVs) – if any, and anything else we need to know about the data. Also tell us which (if any) statistical software you use.
4. Are you thinking of hiring a consultant, or do you just want pointers in some direction?
5. THEN, and ONLY THEN tell us what you’ve tried, why you aren’t happy, and so on.
Themocracy
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hello
I am doing a project on count data using SPSS software. I have analysed the number of calls to a call centre over a 18 month period. It is clear that January shows the highest number of calls. I applied the one way anova test and it showed that there was a significant difference between means. I then carried out a post hoc (LSD) analysis. I looked at the multi-comparisons table and the I-J column (mean differences) for January and it showed some minus numbers when compared to some of the other months. How is it possible that Januarys means can be lower to that of other months when it showed a higher call count? Please could someone explain this to me!
Thank you
If there were other independent variables, then that could account for it. If you only have 18 months of data, then many months will only have one instance. I don’t think ANOVA is right, in this case, as those months will have zero variance and there will be nothing to analyze. (Analysis Of Variance). And, if the number of calls per month is low, you might need to account for the fact that they are counts, which are all going to be integers greater than or equal to 0. (This probably isn’t a problem here, unless it is a very small call center).
You need some other kind of model.
Hi I am hoping some one can help me with my stats. I hoping to find that increasing intake of x will increase levels in subjects. I have 4 groups (1 control) and in each group I will be having two outcomes (measuring maternal levels of X and baby level of X). which statistical test I can use? I think my outcome variable is continuous. am I correct? and how will I know if I have a normal or skewed distribution? I appreciate it if some one can get back to me. thanks
I don’t understand. Why would increasing intake increase levels ? What levels? You ask if you r outcome is continuous, but you also say you have two outcomes….
Mr Flom
I am measuring two things in each group.
for example I am measuring level of X in blood of pregnant women and also measuring the same thing in their babies. My hypothesis is that levels of X in the blood will increase with Higher doses of Treatment A. What I meant by a continuous outcome is that my results are not fixed values (e.g may be 1 or 1.9 ). yes I will have two outcomes (in each group. and I want to compare the two outcome in each group with the control. I just do not know what statistical analysis I can use to come up with a P value .
please answer my question a.s.a.p
does the mean,mode, and median affected when the data is added??
Any of them could be, none of them necessarily are.
Hi,
I need help with choosing a statystical test. I have two grups divided into three categories each. I want to analyze whether the differences in numbers of members in each category is statistically different between groups. The sum of all members within grop is not equal between gropus. Experiment was done in three repeats.
Example (one repeat):
groupI: category A – 11 members, B-9, C-3
groupII: A-3; B – 17, C -14.
guestion: Is the difference between IC and IIC significant?
I can work out the math once I know the test, I just need to be pointed in the right direction. Thanks!
In normal distribution why continuity correction is not apply??? Please answer me
To do this you would need a whole bunch of groups. Right now, in effect, your N is 2
Your question, by itself, makes no sense. Sorry.
Hello, I am doing psychological research regarding happiness and depression. I have over 500 participants who have taken a measure of happiness and a measure of depression. Most of my research is regarding correlations between these 2 measures, but want I really want to do is compare the 90th percentile of both groups. So, those who scored the highest on depression vs those who scored the highest on happiness (I have no overlapping participants who are high in both). My hypothesis is that those who are Happy people have a lower likelihood of scoring higher on the depression measure compared to depressed people scoring higher on the happiness measure (This is the differential relationship between happiness and depression, I apologize if it is confusing. However, my difficulty is whether or not to use 2 different t-tests or to use 2 different correlations. I am also wondering if this can be done in any regard. I have taken upper level statistics and am familiar with conducting both of these tests. Thank you.
Hi David
I think you can do this by comparing two proportions with one test.
Thank you for your reply, but which test should I use?
Hi David – a t-test would do.
And you suggested a single t-test? How would I conduct a single t-test in this manner?
You have two proportions: Proportion of depressed people who are happy and proportion of happy people who are depressed. So, you do a t-test to see which proportion is greater.
Thank you very much sir, I appreciate your help!