Bootstrap Approach in Data Sampling
As shown in the previous chapter, the basic samples of data needed to calculate the confidence intervals have distributions which depart from the traditional parametric distributions. Thus, classical hypothesis-testing procedures based on strong parametric assumptions cannot be used to estimate the confidence intervals. In order to obtain results as reliable as possible, a statistical technique which is applicable regardless of the form of the data probability density function has to be utilized. In other words, this method should make no assumption about the different data distributions. One good candidate is the bootstrap method.
The idea about bootstrapping is that we don’t have enough data. To illustrate this technique, we consider a clothing shop selling second clothing. In a week, sales per day varies with day. The second week analysis also, shows a different trend to first week. As a business owner, one would like to determine the customer behaviour and pattern so that planning can be done effectively to ensure customer satisfaction. Therefore, an average or mean sales need to be determine for the first week. This is done by taking resample data from the main data sample, which will produce a distribution sample as indicated in (a) and (b) for week 2. The t-test statistical analysis will not be the reasonable method to determine the resalable mean value since it will recognise both (a) and (b) as normal distribution, thus giving a
There are a wide variety of techniques used for sampling the evidence of assessment which are all valuable for different reasons. Below are listed these different techniques
Confidence intervals were performed for each color. The confidence interval determines the parameter of the population
Leach, C. (1979). Introduction to statistics: A nonparametric approach for the social sciences. New York: Wiley.
Forecasting the Future Female Veteran Population and Their Increased Use of the VA Medical System - VPT2
Raff also speaks of high failure rates of Hispanics but he fails to account for any success of
12. _____ For a given population, confidence intervals constructed from larger samples tend to be narrower than those constructed from smaller samples. Which statement below best describes why this is true? (A) The variability of the sample mean is less for larger samples. (B) The z-value for larger samples tends to be more accurate. (C) The population variance is larger for large populations. (D) As the sample size increases, the z-value (or t-value) becomes smaller. A machine dispenses potato chips into bags that are advertised as containing one pound of product. To be on the safe side, the machine is supposed to be calibrated to dispense 16.07 ounces per bag, and from long time observation, the distribution of the fill-weights is known to be approximately normal and the process is known to have a standard deviation of 0.15 ounces.
For this assignment we needed to compute the mean, median, and mode for five quantitative variables. The five that were computed in this assignment were number of total prior arrests, number of prior misdemeanors, number of total prior convictions, number of prior felony arrests, and number of drug convictions. The mean is defined as the average in a group of numbers, the median is the middle number in a group, and the mode is the most frequently occurring number in the group.
It sounds like using the stratified random sampling would be a good choice for using a particular group of people. In stratified random sampling the individuals conducting the research know some things about the community that is providing date such as age, gender, ethnicity, and medical diagnosis. This is also a good option when there is a time restraint to obtain the information that is being gathered. The survey would also have to be ensured it is written in a way that the average person can clearly understand the question to get a proper answer.
With the 95% Confidence Interval for Mean, Median, and St Dev are as described above.
The analysis of the data was done by employing the following statistical techniques which were chosen only after the investigator found them to be most appropriate and compatible to the data. Each statistical method is based upon its own specific assumptions regarding the nature of the sample, its universe and research conditions. These factors were considered in advance. Following statistical measures were
The confidence interval is used as a type of interval estimate of a sample population to indicate the reliability of the
“Hypothesis testing is a decision-making process for evaluating claims about a population” (Bluman, 2013, p. 398). This process is used to determine if you will accept or reject the hypothesis. The claim is that the bottles contain less than 16 ounces. The null hypothesis is the soda bottles contain 16 ounces. The alternative hypothesis is the bottles contain less than 16 ounces. The significance level will be 0.05. The test method to be used is a t-score. The test statistic is calculated to be -11.24666539 and the P-value is 1.0. The P-value is the probability of observing a sample statistic as extreme as the test statistic, assuming the null hypothesis is true. The T Crit value is 1.69912702. The calculations show there is enough evidence to support the claim that the soda bottles do
Having the t-test formula we determined the p-value, test statistic, and one –tail test in calculating the hypothesis test.
In order to provide the Australia Park Victoria with the appropriate data to solve its current crisis, the most appropriate method of data collection for this research is the qualitative method. According to Gay and Airasian (p 627) qualitative method is the collection of extensive data on various variables over a long time in a natural setting with an aim of acquiring insights not possible using other methods. It involves three different kinds of information collection: direct observation, in depth and open-ended interviews and written documents. Qualitative method involves use of random sampling and structured data collection instruments that fit different experiences. The method also enables the researcher to study the specific area of
c.)Find a 95% confidence interval for the difference between the above obtained mean starting salaries.