Ese dato es importante para comprender el gráfico.

Ese is a demonstrative adjective meaning that.

In ese dato, it points to a specific piece of information that is not “this one here” but “that one” already mentioned or known from context.

In Spanish, the main options are:

• este / esta = this
• ese / esa = that
• aquel / aquella = that over there / that one farther away

Because dato is a masculine singular noun, the form is ese.

Examples:

• este dato = this piece of information
• ese dato = that piece of information
• aquél dato is old-fashioned spelling; today it would be aquel dato = that piece of information over there / further removed

Dato means piece of information, fact, or data point, depending on context.

In this sentence, ese dato is best understood as:

• that piece of information
• or that data point

A useful distinction:

• un dato = one datum / one piece of information / one data point
• los datos = data / information

So while English often uses data as a mass noun, Spanish commonly uses:

• dato for a single item
• datos for data in general

Spanish has two verbs for to be: ser and estar.

Here, es importante uses ser because importante describes an essential characteristic or quality of the information in this context: it is important.

Use ser for things like:

• identity
• definition
• general characteristics
• inherent or lasting descriptions

Use estar more for:

• states
• conditions
• locations
• results of change

So:

• Es importante = It is important
• Está importante would sound wrong in standard Spanish for this meaning

Yes, adjectives in Spanish usually agree in gender and number, but not all adjectives show a visible change for masculine/feminine.

Importante is an adjective with the same form for both masculine and feminine singular:

• el dato importante
• la información importante

It only changes for number:

• importante = singular
• importantes = plural

Examples:

• Ese dato es importante.
• Esas cifras son importantes.

Para here means for or in order to.

The structure is:

• para + infinitive

This is very common in Spanish and expresses purpose.

So:

• para comprender el gráfico = to understand the graph/chart or in order to understand the graph/chart

Other examples:

• Estudio para aprender. = I study to learn.
• Necesito gafas para leer. = I need glasses to read.

After para, Spanish normally uses the infinitive when the subject is general or the same as the main idea.

So the pattern is:

• para + infinitive

That is why you get:

• para comprender

not:

• para comprende → incorrect, because comprende is a conjugated verb form
• para comprendiendo → incorrect here, because the gerund is not used after para in this way

Both usually mean to understand, and in many contexts they are interchangeable.

• comprender can sound a little more formal or a little deeper, like to fully grasp
• entender is very common in everyday speech

In this sentence, both are possible:

• Ese dato es importante para comprender el gráfico.
• Ese dato es importante para entender el gráfico.

The first may sound slightly more formal or academic, which fits well with dato and gráfico.

Spanish uses definite articles (el, la, los, las) more often than English.

Here, el gráfico means the graph/chart, probably a specific one already known from context.

In English, we might sometimes omit the in similar contexts, but Spanish usually keeps it:

• comprender el gráfico
• analizar la tabla
• leer el texto

Because gráfico is a masculine singular noun, the article is el.

It can mean graph, chart, or sometimes diagram, depending on context.

In educational, scientific, or business contexts, gráfico often refers to a visual representation of data.

So in this sentence, good translations could be:

• the graph
• the chart

The exact choice depends on what kind of image is being referred to.

Gráfico has a written accent because the stress falls on the third-to-last syllable:

• GRÁ-fi-co

Words stressed on the antepenultimate syllable in Spanish always take an accent mark. These are called esdrújulas.

So:

• gráfico
• número
• página

all need written accents.

If you make both the subject and adjective plural, you get:

• Esos datos son importantes para comprender el gráfico.

Changes:

• ese → esos because datos is masculine plural
• dato → datos
• es → son
• importante → importantes

Everything has to agree properly.

Yes, that is also possible, but there are two small points:

1. entender is a valid alternative to comprender
2. gráfica is often used in many Spanish-speaking regions, especially in Latin America, for graph/chart

In Spain, gráfico is very common, especially for a graph or chart in textbooks or reports.
So your version is grammatical, but el gráfico sounds very natural for Spain.

The structure is:

• Ese dato = subject
• es = verb
• importante = predicate adjective
• para comprender el gráfico = purpose phrase

So the sentence is built like this:

[subject] + [ser] + [adjective] + [para + infinitive phrase]

A similar example:

• Esta información es útil para resolver el problema.

This pattern is very common and useful in Spanish.