One-Sample T Tests

Kevin Feasel

2016-09-21

R, T-SQL

Mala Mahadevan shows how to perform one-sample T Tests:

For this post I decided to go with a simple example of how many steps I walked with my per day for the month of August. My goal is 10,000 steps per day – that has been my average over the year but is this true of the data I gathered in August? I have a simple table with two columns – day and steps. Each record has how many steps I took in August per day, for 30 days. So – SELECT AVG(steps) FROM [dbo].[mala-steps] gives me 8262 as my average number of steps per day in August. I want to know if am consistently under performing my goal, or if this is a result of my being less active in August alone. Let me state my problem first – or state what is called ‘null hypothesis’:

I walk 10,000 steps on an average per year. 

Read on for T test operations in T-SQL (although not all operations are available) and R.

Related Posts

Reinforcement Learning with R

Holger von Jouanne-Diedrich takes us through concepts in reinforcement learning: At the core this can be stated as the problem a gambler has who wants to play a one-armed bandit: if there are several machines with different winning probabilities (a so-called multi-armed bandit problem) the question the gambler faces is: which machine to play? He could “exploit” one […]

Read More

Refreshing Views After DDL Changes

Eduardo Pivaral shows how you can refresh the metadata for a view in SQL Server after one of its underlying tables or functions changes: So we proceed to execute an alter view over the first view: ALTER VIEW dbo.[vi_invoices_received_by]ASSELECT ConfirmedReceivedBy as [Received by], COUNT(InvoiceID) as [# of Invoices], CustomerIDFROM Sales.InvoicesGROUP BY ConfirmedReceivedBy, CustomerID;GO So we […]

Read More

Categories

September 2016
MTWTFSS
« Aug Oct »
 1234
567891011
12131415161718
19202122232425
2627282930