Estadistica

Solo disponible en BuenasTareas
  • Páginas : 6 (1355 palabras )
  • Descarga(s) : 0
  • Publicado : 26 de agosto de 2010
Leer documento completo
Vista previa del texto
TALLER DE ESTADÍSTICA DESCRIPTIVA

Enunciado del problema:

1. Pregunte a sus compañeros hombre y mujeres por su estatura y programa al que pertenece y recolecte los datos en el formato como sigue:

1.1 En forma conjunta realice un gráfico y cuadro donde resuma las estadísticas básicas de las estaturas y realice un análisis comparativo de los dos conjuntos de datos. (medias, medianas,desv.estad, coef variac, diagrama boxplot, histograma). (TIPO ENSAYO).

Two-Sample Comparison - Mujeres & Hombres
Sample 1: Mujeres
Sample 2: Hombres

Sample 1: 14 values ranging from 1,53 to 1,68
Sample 2: 14 values ranging from 1,6 to 1,84

The StatAdvisor
This procedure is designed to compare two samples of data. It will calculate various statistics and graphs for each sample,and it will run several tests to determine whether there are statistically significant differences between the two samples.

Summary Statistics
| Mujeres | Hombres |
Count | 14 | 14 |
Average | 1,63 | 1,73786 |
Standard deviation | 0,0392232 | 0,0593787 |
Coeff. of variation | 2,40633% | 3,41677% |
Minimum | 1,53 | 1,6 |
Maximum | 1,68 | 1,84 |
Range | 0,15 | 0,24 |
Stnd.skewness | -1,86738 | -0,732187 |
Stnd. kurtosis | 1,6236 | 0,986541 |

The StatAdvisor
This table shows summary statistics for the two samples of data. Other tabular options within this analysis can be used to test whether differences between the statistics from the two samples are statistically significant. Of particular interest here are the standardized skewness and standardized kurtosis,which can be used to determine whether the samples come from normal distributions. Values of these statistics outside the range of -2 to +2 indicate significant departures from normality, which would tend to invalidate the tests which compare the standard deviations. In this case, both standardized skewness values are within the range expected. Both standardized kurtosis values are within therange expected.

Comparison of Standard Deviations
| Mujeres | Hombres |
Standard deviation | 0,0392232 | 0,0593787 |
Variance | 0,00153846 | 0,00352582 |
Df | 13 | 13 |
Ratio of Variances = 0,436341

95,0% Confidence Intervals
Standard deviation of Mujeres: [0,028435, 0,0631903]
Standard deviation of Hombres: [0,0430468, 0,0956615]
Ratio of Variances: [0,140076,1,35922]

F-test to Compare Standard Deviations
Null hypothesis: sigma1 = sigma2
Alt. hypothesis: sigma1 NE sigma2
F = 0,436341 P-value = 0,14795
Do not reject the null hypothesis for alpha = 0,05.

The StatAdvisor
This option runs an F-test to compare the variances of the two samples. It also constructs confidence intervals or bounds for each standard deviation and for theratio of the variances. Of particular interest is the confidence interval for the ratio of the variances, which extends from 0,140076 to 1,35922. Since the interval contains the value 1, there is not a statistically significant difference between the standard deviations of the two samples at the 95,0% confidence level.

An F-test may also be used to test a specific hypothesis about the standarddeviations of the populations from which the two samples come. In this case, the test has been constructed to determine whether the ratio of the standard deviations equals 1,0 versus the alternative hypothesis that the ratio does not equal 1,0. Since the computed P-value is not less than 0,05, we cannot reject the null hypothesis.

IMPORTANT NOTE: the F-tests and confidence intervals shownhere depend on the samples having come from normal distributions. To test this assumption, select Summary Statistics from the list of Tabular Options and check the standardized skewness and standardized kurtosis values.

Comparison of Medians
Median of sample 1: 1,635
Median of sample 2: 1,74

Mann-Whitney (Wilcoxon) W-test to compare medians
Null hypothesis: median1 = median2...
tracking img