## What is meant by sphericity?

Sphericity is a measure of how spherical an object is. Proposed by Waddell in 1935, the sphericity of a particle is defined as the ratio of the surface area of an equal-volume sphere to the actual surface area of the particle: [2.21]

## Why is the repeated measures Anova more powerful than the between groups Anova?

More statistical power: Repeated measures designs can be very powerful because they control for factors that cause variability between subjects. Fewer subjects: Thanks to the greater statistical power, a repeated measures design can use fewer subjects to detect a desired effect size.

**How do you calculate a surface area?**

Surface area is the sum of the areas of all faces (or surfaces) on a 3D shape. A cuboid has 6 rectangular faces. To find the surface area of a cuboid, add the areas of all 6 faces. We can also label the length (l), width (w), and height (h) of the prism and use the formula, SA=2lw+2lh+2hw, to find the surface area.

### What is the difference between a randomized Anova and a repeated measures Anova What does the term one-way mean with respect to an Anova?

The term “randomized” indicates that subjects were randomly assigned to conditions (Jackson, 2012). Correlated-groups designs use a “repeated-measures” ANOVA (Jackson, 2012). The term “repeated-measures” indicates that measures were repeatedly taken on the same subjects (Jackson, 2012).

### What if Mauchly’s test of sphericity is significant?

→ If Mauchly’s test statistic is significant (i.e. has a probability value less than . 05) we conclude that there are significant differences between the variance of differences: the condition of sphericity has not been met. → If Mauchly’s test is significant then we cannot trust the F-ratios produced by SPSS.

**What is the primary advantage of the repeated measures Anova compared to the between subjects Anova?**

What is the primary advantage of the repeated-measures ANOVA, compared to the between-subjects ANOVA? Repeated-measures ANOVA maximizes error. Repeated-measures ANOVA allows us to compare more than three groups of participants. Calculation of error is easier in a repeated-measures design.

#### What is effective surface area?

A concept of effective surface area was defined as a geometrical controlling factor for a chemical reaction involving powdery materials. It is not uniquely determined for the specific material but depends on the sort of chemical reaction as well as the state of agglomeration.

#### How do you find a specific surface area?

The specific surface area of a powder is determined by physical adsorption of a gas on the surface of the solid and by calculating the amount of adsorbate gas corresponding to a monomolecular layer on the surface.

**What is the difference between roundness and sphericity?**

Sphericity is a measure of the degree to which a particle approximates the shape of a sphere, and is independent of its size. Roundness is the measure of the sharpness of a particle’s edges and corners. Sphericity and roundness are ratios and, therefore, dimensionless numbers.

## How do I report a violation of sphericity?

Violations of Sphericity and Greenhouse-Geisser Corrections If so, report chi-squared (χ2), degrees of freedom, p and epsilon (ε) as below and report the Greenhouse-Geisser corrected values for any effects involving this factor (rounded to the appropriate decimal place).

## What is surface area volume?

The surface-area-to-volume ratio, also called the surface-to-volume ratio and variously denoted sa/vol or SA:V, is the amount of surface area per unit volume of an object or collection of objects.

**How do you calculate sphericity?**

Sphericity has a maximum value of 1, which corresponds to a particle with a perfectly spherical shape. The smaller its value, the lesser its resemblance to a sphere. and is represented as Φp = 6*(Vp/(Sp*ρp)) or particle_sphericity = 6*(Volume of one Particle/(Surface Area of a Particle*Density of Particle)).

### What is sphericity in geography?

sphericity (sphe-ric’-i-ty). The relation to each other of the various diameters (length, width, thickness) of a particle; specif. the degree to which the shape of a sedimentary particle approaches that of a sphere.

### How do I report Anova results?

Report the result of the one-way ANOVA (e.g., “There were no statistically significant differences between group means as determined by one-way ANOVA (F(2,27) = 1.397, p = . 15)”). Not achieving a statistically significant result does not mean you should not report group means ± standard deviation also.

**What is the relationship between sphericity roundness and rigidity?**

Sphericity is a measure of the degree to which a particle approximates the shape of a sphere, and is independent of its size. Roundness is the measure of the sharpness of a particle’s edges and corners.

#### What is sphericity used to find?

Geologists can use sphericity to study the aerodynamics of volcanic particles. Three-dimensional laser scanning and scanning electron microscope technologies have directly measured the sphericity of volcanic particles.

#### What is meant by homogeneity of variance?

Homogeneity of variance is an assumption underlying both t tests and F tests (analyses of variance, ANOVAs) in which the population variances (i.e., the distribution, or “spread,” of scores around the mean) of two or more samples are considered equal.

**What is Bartlett’s test of sphericity?**

Bartlett’s Test of Sphericity compares an observed correlation matrix to the identity matrix. Essentially it checks to see if there is a certain redundancy between the variables that we can summarize with a few number of factors. The null hypothesis of the test is that the variables are orthogonal, i.e. not correlated.

## What is roundness ratio?

Roundness ratio is determined by comparing (divide) the equatorial measurement to the polar measurement. A perfectly round object would have the same measurements and dividing equatorial by polar measurement would result in a 1.000 RR.

## Which of the following gives the total surface area of the particle?

Which of the following gives the total surface area of the particle? Explanation: The total surface area of the particle is given by A = N*Sp, where N is the number of the particles and Sp is the surface area of individual particle.

**Which method is used to determine surface area of particle?**

The most widely used method for surface-area determination is low-temperature gas adsorption, particularly nitrogen and krypton at liquid-nitrogen temperature. Most gases can and have been used, and these include water vapour at room temperature and carbon dioxide at room temperature and at −78°C.

### What is a between subjects Anova?

Between-Subjects ANOVA: One of the most common forms of an ANOVA is a between-subjects ANOVA. This type of analysis is applied when examining for differences between independent groups on a continuous level variable. A factorial ANOVA can be applied when there are two or more independent variables.